EP1888915A2

EP1888915A2 - Aerovortex mill

Info

Publication number: EP1888915A2
Application number: EP06745028A
Authority: EP
Inventors: Michael Stavrou Kilaras
Original assignee: Individual
Current assignee: Individual
Priority date: 2005-06-01
Filing date: 2006-05-26
Publication date: 2008-02-20
Also published as: WO2006129254A2; WO2006129254A3; CY2535B1; US20060275122A1

Abstract

The invention relates to the use of Wind Turbines for power generation. It seeks to provide those areas with low winds, a pioneering way to harness efficiently the energy of the wind. In order to achieve this, the invention makes use of a VIASAD/VIFSAD/JETIASAD/VoPAC pressure differential mechanism. The VIASAD/VIFSAD/ JETIASAD/VoPAC device compresses and accelerates the wind or underwater current inflow (Primary Flow) and then it generates high-speed flow along with vortices. Ultimately, the device intercepts or controls passively and/or actively the generated vorticity. The combined result of the generated high- speed flow and vortices is the creation of a suction flow (Secondary), which can be used in the following two ways: (1) Drive the secondary air flow through a turbine fan and/or (2) Suppress adverse pressure gradients on the surface of wind/water turbine rotor blades, which results in improving the output performance of the turbine.

Description

Aerovortex Mill

[0001] The invention relates to the use of Wind Turbines for power generation .

[0002] Wind constitutes one of the major sources of renewable or "green" energy production. Windmills are widely used all over the world in order to harness the power from the wind.

[0003] Currently there are two types of windmills: vertical axis and horizontal axis machines. They both use some kind of propeller which is primarily used for extracting or converting the Kinetic Energy of the wind into mainly two types of energy: (1 ) Electrical energy (Power generators) and (2) Potential energy of the water (Water pumps) . These propellers or rotors are either drag-based or lift-based devices. The drag-based rotors have slower rotational speeds than the lift-based devices. Generally the lift-based devices are a lot more efficient than the drag- based devices, and consequently the wind power generators are mostly lift-based devices.

[0004]A lot of research and development has been done around the world in order to improve the efficiency and performance of lift-based windmills. This lead to a number of considerable advances in this field, primarily focused on the following three areas:

1. The aerodynamics of the rotor blades.

2. Wind mill yaw control and rotor blade pitch control . 3. Improvement of the gear system which amplifies rotation from the main rotor with the blades to the generator.

[0005] The wind as an energy resource: Large areas of the world appear to have mean annual windspeeds below 3.0m/s, and are unsuitable for wind power systems, and almost equally large areas have wind speeds in the intermediate range of 3.0-7.0m/s (Class 4, 5) where wind power may or may not be an option. These areas, are mainly unexploited for harnessing the wind energy, because technology does not exist to serve efficiently this purpose yet.

[0006] Those areas with mean annual wind speeds exceeding 7.0m/s (Class 6) are the most economically viable for power generation. However, wind development of Class 6 sites will soon reach its limit as they will be fully developed in the near future. As a result, if advances in technology are not able to make low-wind speed sites more cost effective, wind energy will plateau.

[0007] In summary, the most efficient current technology based on lift-generating rotor wind mills, can operate in areas with mean annual wind speeds exceeding 7.0 m/s and generate enough useful energy or electricity to justify their extremely high cost. On the other hand, areas with low mean annual wind speeds (below 7.0m/s), are left with no reliable and efficient enough technology to harness the energy of the wind. The invention seeks to provide those areas with low winds, a pioneering way to harness efficiently the energy of the wind and hence make wind energy cost effective in low wind areas.

[0008] The invention has been inspired by a variety of lessons from nature, where highly efficient mechanisms are being deployed in order to harness energy from the flow and use it to generate Lift and Thrust. Specifically, these are the Hydrodynamic Mechanisms of Aquatic Locomotion used by fish to propel their way through fluids and the Flight Propulsion Mechanisms used by birds and insects moving through Air. The fundamental idea behind all these mechanisms is that both aquatic and airborne animals, use different moving body parts to compress their living fluid medium (Water or Air) in order to accelerate it with respect to their bodies and eventually generate vortices. These vortices constitute high energy density fluid structures or patterns, and as result they can be used by fish and birds in order to efficiently harness the energy they need, as they transform it from one form to the other (Mechanical -> Fluid Pressure -> Mechanical) .

[0009] The primary goal of the invention, is to increase the efficiency by which wind/air/water turbines convert the Kinetic Energy per unit volume of the incoming flow (Dynamic Pressure) to Mechanical Energy (Rotation of Blades) . In order to achieve this in an efficient way, the proposed idea is attempting to imitate the basic principles behind Aquatic Locomotion and Flight Propulsion, in which energy is efficiently harnessed as it is transformed from one form to the other. Specifically, the invention is a device which can take various forms or configurations. This device makes use of low-energy density fluid flow, which is readily available in nature, and converts it to high-energy density flow structures like vortices, which can be efficiently used to improve the aerodynamic characteristics of wind/air/water turbines, resulting in enhancing their power output. (Figure 26)

[0010] The devices or mechanisms proposed by the invention, which are responsible for increasing the energy density of the incoming flow and thus rendering their use efficient in improving the output performance of wind/air/water turbines, are the following:

1. VIASAD/VIFSAD: Vortex Induced Air/Flow Speed Amplification

Device .

2. JETIASAD/JETIFSAD: Jet stream Induced Air/Flow Speed Amplification Device.

[0011] The following is a brief description of the above invention mechanisms: (1) VIASAD was originally given this name, assuming its operation in wind or air. It can very well though, be used in water, like for example harnessing the energy from underwater currents in oceans. So more generally it can be called VIFSAD which stands for: Vortex Induced Flow Speed Amplification Device. The VIASAD device initially compresses the incoming flow, and then it directs the accelerated and hence high-energy density air/water flow, past vortex generators in order to generate vortices. The vortices are then compressed by restricting their path, using flaps, nozzles or any other device for this purpose, in order to accelerate them and as a result amplify the generated suction effect. (2) JETIASAD can also be given the general name JETIFSAD: Jet stream Induced Flow Speed Amplification Device as it can operate in both air and water or generally in any fluid. The JETIASAD device is basically a simple pressure differential device, which consists of a converging nozzle of any type, used for compressing and accelerating the incoming flow. In both the VIASAD and JETIASAD devices, the accelerated flow (high-speed jet) along with the generated high-speed vortices, constitute the Primary Flow, which is responsible for the created suction effect .

[0012] The combined effect of the high-speed jet stream and vortices generated by either the VIASAD/VIFSAD or the JETIASAD device, is the decrease in static pressure which induces the suction effect, that eventually gives rise to a suction air flow (Secondary Air Flow) .

[0013] The Secondary air/water Flow can be used in the following ways in order to either drive air/water turbines or enhance the efficiency by which wind/air/water turbines harness the wind/water flow energy across their whole operational flow speed spectrum, and especially at low wind/air/water speeds:

(1) Accelerated air flow (Secondary Flow) drives a turbine as it is passed through the rotating blades of axial impellers or centrifugal impellers or any other type of impeller placed inside a housing. The housing efficiently directs air through an inlet into the rotating impellers and then through an outlet into a duct which eventually leads to the region within the pressure differential device (VIASAD/ JETIASAD) where suction takes place.

(2) Use of the Secondary Flow as an Adverse Pressure Gradient suppressor on blades or wings or lifting surfaces used by air turbine devices. Basically, low pressure generated by the pressure differential device VIASAD/ JETIASAD, sucks slow-moving air from the surface of a wind turbine rotor blades or lifting surfaces. The slow-moving air is confined within a region close to the surface, called boundary layer. Suction occurs through hole or slot-perforated surface area on the blades. The location of the holes or slots is chosen in such way in order to serve optimally any of the following goals: (i) For wind speeds below the rated wind speed of a wind turbine (Wind turbine reaches maximum power output), operate the wind turbine with its blades at high angles of attack to the relative air flow, where stall occurs, and use the secondary flow to suppress stall in order to keep the flow attached to the surface and as a result achieve higher than normal Lift Coefficients. In this way, it is even possible to exceed the maximum Lift Coefficient for the blade. Also, corresponding Drag Coefficients will be lower, and consequently the Lift-to- Drag (L/D) ratio will increase, effectively improving the output performance of the wind turbine. The suppression of stall mentioned above, requires suction in order to eliminate the reverse flow or the stall bubble on the low-pressure surface of the blade/wing/lifting surface. This usually takes place over the three quarter (3/4) chord-length area from the trailing edge of the rotor blades/lifting surfaces, but it can also extend beyond this area.

(ii) Use the secondary flow in stall-controlled rotors, when the wind speed exceeds the rated wind speed of a wind turbine (maximum power output), in order to achieve the following: Make the separated area or the stall bubble on the blades extend in such a way, that the extracted power remains relatively constant, independent of the wind speed flactuations, and at cut-out (Operation stops) the power available in the wind exceeds the maximum power output of the turbine by a certain factor. Currently for commercially available, utility size wind turbines, this factor has an optimum value between 8 and 10. In order to achieve the above, a feedback control system will have to be used to adjust the flow rate of the secondary/suction flow continuously.

(iii) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow Control (HLFC) in order to minimize skin-friction and pressure drag of the rotating/moving wind turbine blades/lifting surfaces. Basically, use the generated secondary/suction flow in order to keep the flow over the blade/wing/lifting surface laminar and delay transition to turbulence. The Laminarization of the flow results in lower overall drag and smooth as well as attached air flow at any angle of attack, which effectively gives higher Lift and lower Drag. This requires suction of the slow-moving air close to the surface (Within the Boundary Layer) , and it usually needs to occur, but it is not restricted to over a third (1/3) of the chord-length from the leading edge of the wing/blade.

[0014] Aerovortex Mill, as proposed by the invention, consists of a wind/air/water turbine, which is using one of the pressure differential mechanisms: VIASAD/VIFSAD or JETIASAD, in order to enhance or maximize its power output performance in the different ways described above. This combination of the turbine and the VIASAD/VIFSAD or JETIASAD mechanisms can take various forms. Three (3) recommended ways to do this, but it's not restricted to, are the following: (1) Rotor Hub Variant: Integrate the pressure differential mechanism (VIASAD/VIFSAD or JETIASAD) in the rotor hub of the wind/air/water turbine. The rotor hub is the optimum location for installing the pressure differential mechanism, because it is exposed to the same energy-density flow as the rest of the rotor, but it contributes a lot less to the power output compared to the part of the blades at the tip. Effectively, with this configuration, we can redirect the energy harnessed at the rotor hub to the tips of the rotor blades, and by doing this, we can utilize this input energy more effectively in generating power output. The incoming energy at the hub is harnessed and converted to suction which is ultimately used to augment the aerodynamic characteristics of the blade at the tip and as a result increase the generated torque and hence the power output of the turbine. (2) Off-the-Rotor Variant: Attach the pressure differential mechanism (VIASAD/VIFSAD or JETIASAD) on the wind/air/water turbine in such a way, so that its intake is not obstructed by the rotating rotor blades of the turbine. A structure supporting the VIASAD/VIFSAD or JETIASAD device and connected to the body/nacelle of the turbine behind the rotor will have to be used. The structure needs to extend beyond the rotor swept area. (3) Stand-Alone Variant: Install the pressure differential mechanism (VIASAD/VIFSAD or JETIASAD) on a separate tower or support structure, independent of the wind/air/water turbine assembly.

[0015] Currently, the mechanical efficiency of commercial wind turbines is maximized at wind speeds above 7m/s, usually around some 9m/s. The thinking behind this, is that efficiency is not important at low wind speeds since there is not much energy to harness at low winds. Consequently, in low wind areas the choices available are to either not harness the wind energy at all, or harness it with very low mechanical efficiency using existing wind turbine technology. Aerovortex Mill will help close this gap by allowing the efficient harnessing of energy from the wind at very low wind speeds. It will also increase the output performance efficiency at all other speeds as well.

[0016] Aerovortex Mill makes use of a contraction or a converging nozzle in combination with vortex generators, in order to increase the density of the input energy of the wind and as a result improve its efficiency at low winds. By carefully selecting the design characteristics of the converging nozzle (Inlet Area, Ratio of Inlet to Outlet cross-sectional Area) , the compression and hence acceleration of incoming air flow will lead to generation of vortices with persistent strength that can sustain enough suction for improving the aerodynamics of wind turbine blades/lifting surfaces as described above. The result is lower cut-in wind speed and enhanced Lift-to-Drag ratio for the wind/air/water turbine. The enhanced Lift-to-Drag (L/D) ratio, means more generated torque on the rotor blades and hence higher power output.

[0017] The Power available in the wind is given by the following formula: P=O .5* (Density) *A*V³.

So in order to harness more energy from the wind, a larger rotor area needs to be exposed to the incoming flow. This is exactly what current commercial wind turbine technology is doing by making use of large rotor blades. By doing this, they maximize the area being swept when they operate, and hence maximize the amount of energy harnessed. However, the use of large massive blades, increases the inertial forces on the rotor, which results in : (1) Higher cut-in wind speeds than expected. (2) Poor overall performance (low efficiency) at low wind speeds. (3) Increased noise generation.

The invention, will help deliver improved performance at low wind sites without the need for increased rotor size, lower the cut-in wind speed and reduce noise. [0018] The solution of using taller towers for installing Wind Turbines so that they can reach for higher wind speeds, is very costly and technologically challenging. The invention can eliminate the need for excessive tower heights by increasing the performance of existing wind turbines installed on current tower technology .

[0019]As mentioned above, current commercial wind turbines are optimized for a single design wind speed where they achieve maximum output performance efficiently. Consequently, most of the time, at all other wind speeds, they operate at low efficiency. Aerovortex Mill will operate with comparable efficiency over a wide range of wind speeds.

[0020 ] Considering the case where the induced secondary flow generated by the invention mechanisms is used to drive impellers enclosed in housings, the proposed idea has the following advantage: The housing isolates the impellers from wind gusts and as a result it protects them from rapid flactuations of wind speed. Also, it protects the impellers from turbulence generated when the wind flows past buildings or other obstacles. This improves dramatically the reliability and maintenability of the gear box connected to the shaft driven by the impellers and makes the Aerovortex Mill more reliable and cost effective. (Note that the gear box is ultimately connected to the generator) .

[0021] The invention will now be described with reference to the accompanying drawings:

[0022]At the center of the functionality of the invention is the use of the following two mechanisms, which are responsible for generating the suction that suppresses separated or slow-moving air from the surface of turbine blades/lifting surfaces and also it can be used to drive the air flow through the Mill fan or impeller in order to set it in motion :

1. VIASAD/VIFSAD : Vortex Induced Air/Flow Speed Amplification Device .

2. JETIASAD/JETIFSAD: Jet stream Induced Air/Flow Speed Amplification Device.

[0023] The source of inspiration for the recommended mechanisms (VIASAD / JETIASAD) , consists of specific lessons from nature which can be summarized as follows: The Hydrodynamic mechanisms of Aquatic Locomotion used by fish to propel their way through fluids and the Flight propulsion mechanisms used by birds and insects moving through Air. This idea is illustrated further in Figures 1, 2 and 3.

[0024 ] Figures 1 and 2 illustrate the Aquatic Locomotion which can be summarized as follows:

The Momentum-Impulse Couple of Vortex REAR DRIVEN Bodies: The rear body parts (feet, caudal fin) can both (A) accelerate the vortex flow generated by the body moving through the water and/or (B) generate vortices:

A. The vortex flow generated by the body of the fish is allowed to expand laterally and eventually it is beaten by the caudal fin. This effectively restricts its path and hence the vortex flow is being accelerated.

B. The rear body parts preform the aquatic surroundings by applying some work on the water, which in turn stores this energy. The preformed water masses flow into the zone of the underpressure creating a rolling vortex (Ungerechts et al) . Due to the high geometrical organization, vortices

'carry a high amount of momentum in relation to the energy spent for their production' (Lighthill, 1969). The generated trailing vortex induces a velocity field which is influencing the flow in front of the moving body. [0025] Figure : 1. Human Swimmer. Related Figures: 2, 3.

Part terminology: Jet stream (1), Vortex (2) . Description: The feet strokes up and down in the water generate ^Λbarrel' like trailing vortices (2) . These vortices are the cause for a backward-moving jet stream (1) in between them, and as a result the swimmer acquires forward momentum. It looks as if the human body is translating through the water between rollers.

[0026] Figure : 2. Shark/Fish Locomotion - Tail Stroke movements. Related Figures: 1, 3.

Part terminology: Shark (1), Vortex (2), Generated Jet Stream (3) , Shark Tail (4) . Description: The periodical (left/right) movement of the shark' s caudal fin shreds vortices on each side which are rotating in an opposite sense (Blickman, 1992) . Due to the lasting rotation of the generated vortices, a jet stream is produced. This jet stream flows in between the trailing vortices and with a direction opposite to the direction of travel of the shark (backwards) . The thrusting impulse responsible for pushing the shark forwards is a reaction to this jet stream (similar to the jet stream behind modern aircraft) .

[0027] Figure : 3. Insect Flight - Flapping Wings. Related Figures: 1, 2.

Part terminology: Insect (1), Wing Section (2), Generated Vortex (3), Jet Stream (4). Description: The very slow velocities by which insects fly in the air and hence the low Reynolds numbers associated with these velocities, do not justify the lift generated on their wings in order to keep them airborne. For this reason, insects use flapping along with rotational movement of their wings, in order to increase the airflow in the vicinity of each of their flapping wings and in this way generate the required lift so that they are able to fly. The way this is achieved is by generating wing leading-edge vortices (LEV) (3) which in turn produce a jet stream (5) on top of the wing.

[0028] Figure :4A. Multiple inlet VIASAD/VIFSAD - Front View. Related Figures: 4B, 4C.

Part Terminology: Throat Tube (1), Suction Flow Tubes (2), Inlet to Blower Fan (3), JETIASAD/VIASAD Inlet (4), Conical Blower Fan (5), Conical Hub (6) (For diverting air flow to the fan blades) .

Description: In this variant, the VIASAD/JETIASAD device consists of multiple converging nozzles with circular inlets facing the wind. The incoming air is accelerated and then vortices are being generated. The accelerated vortical flow induces suction which drives a secondary flow through the fan, then the fan outlet and finally through a suction flow tube which leads to the vortical and/or accelerated incoming wind flow .

[0029] Figure :4B. Multiple inlet VIASAD/VIFSAD - Top View. Related Figures: 4A, 4C.

Part Terminology: Outlet (1), Diffuser (2), Throat Pipe (3), Suction Flow Tube (4), Contraction (5), Inlet (6), Wind (7), Convergent Nozzle (8), Inlet to Fan (9), Fan Casing (10), Conical Blower Fan (11), Flow Deflector Wall (12). Description: This is the top view of the variant described in figure 4A.

[0030] Figure :4C. Multiple inlet VIASAD/VIFSAD - Side View. Related Figures: 4A, 4B.

Part Terminology: Wind (1), Conical Blower Fan (2), Contraction (3), Air Flow Deflector (4), Shaft (5), Diffuser (6), Outlet (7), Suction Tube (8), Sucked Air (9), Fan Outflow Guide Wall (10), Inlet (11). Description: This is the side view of the variant described in figure 4A.

[0031] Figure :5A. Dual-inlet VIASAD/VIFSAD Variant - Front View.

Related Figures: 5B, 5C, 5D, 5E.

Part Terminology: VIASAD/VIFSAD Inlet (1), Contraction (2), Vortex Generator (3), Suction Flow Tube (4), Fan Casing (5), Conical Blower Fan (6), Inlet to Blower Fan (7), Conical Hub Air Flow Deflector (8) .

Description: A VIASAD/VIFSAD device consisting of two 2D contraction nozzles. The two converging nozzles guide the accelerated wind inflow past vortex generators in order to create vortices. The vortices are further being accelerated as they go through the contraction inducing suction, which drives a secondary flow through the fan, the fan outlet and finally through a suction flow tube.

[0032] Figure :5B. Dual-inlet VIASAD/VIFSAD Variant - Top View. Related Figures: 5A, 5C, 5D, 5E.

Part Terminology: Suction Flow Tube (1), VIASAD/VIFSAD Inlet (2), Wind (3), Intake Nozzle (4), Conical Blower Fan (5), Inlet to Fan (6), Fan Casing (7), Contraction or Converging Nozzle (8), Outflow (9), Shaft (10), Air Flow Deflector (11), Contraction Outlet (12), Diffuser (13).

Description: This is the top view of the variant described in figure 5A. The impeller shown is a conical blower fan.

[0033] Figure :5C. Dual-inlet VIASAD/VIFSAD Variant - Top View. Related Figures: 5B, 5C, 5D, 5E.

Part Terminology: Suction Flow Tube (1), VIASAD/VIFSAD Inlet (2), Wind (3), Intake Nozzle (4), Multistage Axial Fan (5), Inlet to Fan (6), Fan Casing (7), Contraction or Converging Nozzle (8), Outflow (9), Shaft (10), Air Flow Deflector (11), Contraction Outlet (12), Diffuser (13). Description: This is the top view of the variant described in figure 5A with axial fans arranged in series.

[0034]Figure:5D. Dual-inlet VIASAD/VIFSAD Variant - Side View. Related Figures: 5A, 5B, 5C, 5E.

Part Terminology: Contraction (1), Suction Flow Tube (2),

Diffuser (3) , Conical Blower Fan (4) .

Description: This is the side view of the variant described in figure 5A with one type of the contraction inlet nozzle.

[0035] Figure :5E. Dual-inlet VIASAD/VIFSAD Variant - Side View.

Related Figures: 5A, 5B, 5C, 5D.

Part Terminology: Contraction (1), Suction Flow Tube (2),

Diffuser (3) , Conical Blower Fan (4) . Description: This is the side view of the variant described in figure 5A with another type of the contraction inlet nozzle.

[0036] Figure: 6. Dual-Inflow VIASAD/VIFSAD Variant - 3D View.

Related Figures: 7, 8, 9, 10. Part Terminology: Air Suction Tube (1), Diffusion Nozzle (2),

Fan/Fan Housing (3), Branch Suction Tube (4), VIASAD/VIFSAD

(5) , Air Inflow (6) .

Description: This is a 3D view of a variant with two

VIASAD/VIFSAD devices. Suction induced in the VIASAD/VIFSAD devices drive the secondary air flow through the fans which are connected to the air suction tubes.

[0037] Figure: 7. Dual-Inflow VIASAD/VIFSAD Variant - 3D View.

Related Figures: 6, 8, 9, 10. Part Terminology: Air Suction Tube (1), Fan Inlet (2),

Diffusion Nozzle (3), VIASAD/VIFSAD device (4), Fan/Fan

Housing (5), Air Inflow (6).

Description: This is a 3D view of a variant with two

[0038] Figure: 8. Dual-Inflow VIASAD/VIFSAD Variant - 3D View.

Related Figures: 6, 7, 9, 10. Part Terminology: Air Suction Tube (1), Fan/Fan Housing (2),

Fan Outlet (3), Diffusion Nozzle (4), VIASAD/VIFSAD (5), Fan

Inlet (6), Air Inflow (7).

Description: This is a 3D view of a variant with two

[0039] FIGURE: 9. A pressure differential device (VIASAD/VIFSAD) generates suction flow which drives an Axial Air Turbine.

Related Figures: 4A to 8.

Part Terminology: Wind (1), Pressure Differential Device (VIASAD/VIFSAD) (2), Vortices (3), Low Pressure Chamber of the VIASAD/VIFSAD device (4), Suction Tube with Secondary/Suction flow (5), Axial Impeller (6), Air Turbine Housing (7), Air Intake (8).

Description: Suction generated by the pressure differential device (VIASAD/VIFSAD) drives the flow through an Axial Impeller enclosed in a housing.

[0040] FIGURE: 10. A pressure differential device (VIASAD/VIFSAD) generates suction flow which drives a Centrifugal Impeller/Air Turbine. Related Figures: 4A to 9. Part Terminology: Centrifugal Impeller/Air Turbine (1),

Exhaust Nozzle (2), Intake of the Centrifugal Air Turbine (3), Suction Tube with Secondary flow (4), Low Pressure Chamber of the pressure differential device (VIASAD/VIFSAD) (5) , Vortices (6), Pressure Differential device (VIASAD/VIFSAD) (7) , Wind (8) . Description: Suction generated by the pressure differential device (VIASAD/VIFSAD) drives the flow through a Centrifugal Impeller enclosed in a housing.

[0041]Figure:ll. VIASAD/VIFSAD Device. Related Figures: 12, 13, 26.

Part Terminology: Air Inflow (1), Contraction Nozzle (2), Vortex Generator (3), Vortex Lateral Expansion Chamber (4), Hinge (5), Air Suction Tube (6), Diffusion Nozzle (7), Low Pressure Region (8), Vortex Lateral Contraction Mechanism (9), Vortex (10) .

Description: This is the side section view of a VIASAD device. The air inflow is initially compressed and thus its energy per unit volume increases. Vortex generators are then used to generate vortices. These vortices are allowed to expand laterally and eventually are accelerated by restricting their path towards the outlet. The accelerated vortices induce suction which in turn drives the secondary flow that can be used either to drive turbines or suppress adverse pressure gradients on rotating blades.

[0042]Figure:12. VIASAD/VIFSAD - Wind Turbine APG suppressor. Related Figures: 11, 13, 24, 25A/B, 26. Part Terminology: Rotor hub (1), Rotor Blade (2), VIASAD Contraction (3), VIASAD Suction Flow (4), Low Pressure Chamber (5), VIASAD Diffuser (6), Vortex (7), Vortex Generator (8), Wind (9) .

Description: This diagram illustrates the principle of using the suction generated by a VIASAD/VIFSAD device, in order to suppress adverse pressure gradients on the rotor blades of a turbine. This is achieved by absorbing slow-moving air on the low-pressure surface of the rotor blades. As a result the flow stays attached and smooth even at high angles of attack. The blade's lift coefficient decreases, its corresponding drag coefficient decreases and hence the Lift-to-Drag (L/D) ratio increases, which effectively results in enhancing the turbine's performance.

[0043] Figure: 13. VIASAD/VIFSAD - Rotor Hub Variant. Related Figures: 14, 24, 25A/B, 26, 27, 28.

Part Terminology: Contraction (1), Vortex Generator (2), Generated Vortex (3), Vortex Lateral Expansion Mechanism (4), Low Pressure Chamber (5) , Vortex Lateral Contraction Mechanism (6), Sliding bar/axle (7), Diffusion Nozzle (8), Air Suction Tube (9) .

Description: This diagram illustrates the basic functional principles for the Rotor Hub Variant of a VIASAD/VIFSAD device. This Variant harnesses energy incoming at and around the rotor hub and redirecting it to the blade tips. This energy is then used to augment the aerodynamic characteristics of the blade at the tip and as a result increase the generated torque and hence the Power Output of the turbine. Specifically, the device generates suction by harnessing the energy compressed/stored in the generated vortical flow. The suction is ultimately used to suppress adverse pressure gradients on the rotor blades by absorbing slow-moving air on their low-pressure surface. The result is attached and smooth flow at higher angles of attack, increasing the blade' s lift- to-Drag (L/D) ratio.

[0044] Figure: 14. VIASAD/VIFSAD - Rotor Hub Variant. Related Figures: 13, 24, 25A/B, 26, 27, 28.

Part Terminology: Wind Turbine Tower (1), Wind (2), Intake of the VIASAD/VIFSAD device (3), VIASAD/VIFSAD device (4), Wind Turbine Blade (5) .

Description: This diagram illustrates a wind turbine with a VIASAD/VIFSAD device integrated at its rotor hub. The Rotor Hub Variant of the VIASAD/VIFSAD device harnesses energy incoming at and around the rotor hub and redirecting it to the blade tips. This energy is then used to augment the aerodynamic characteristics of the blade at the tip and as a result increase the generated torque and hence the power output of the turbine. Specifically, the device generates suction by harnessing the energy compressed/stored in the generated vortical flow. The suction is ultimately used to suppress adverse pressure gradients on the rotor blades by absorbing slow-moving air on their low-pressure surface. The result is attached and smooth flow at higher angles of attack, increasing the blade's lift-to-Drag (L/D) ratio. The rotor hub is the optimum location for installing the VIASAD/VIFSAD device, since it is exposed to the same energy density of the incoming flow as the rest of the rotor, but it contributes a lot less compared to the blade tips, to the overall turbine Power output. The aerodynamic force on the blades around the rotor hub, could contribute a lot more to the generated torque on the rotor and hence the Power Output, if it was applied at the tips of the blades. The Rotor Hub Variant aims to achieve exactly this, by harnessing energy incoming at and around the rotor hub and redirecting it to the blade tips.

[0045] FIGURE: 15. Wind Turbine fitted with an Off-the-Rotor VIASAD/VIFSAD device variant. Related Figures: 11-26. Part Terminology: Rotor Blade (1), Wind Turbine (2), Wind Turbine Tower (3), Suction Flow - Secondary Flow (4), VIASAD/VIFSAD device (5), Wind (6).

Description: The VIASAD/VIFSAD device is attached to a single wind turbine. The suction or secondary flow that generates drives the Active/Laminar Flow Control on the rotor blades (Suppression of Adverse Pressure Gradients) .

[0046] FIGURE: 16. 3D view of a Wind Turbine fitted with a Dual inflow Off-the-Rotor VIASAD/VIFSAD device variant. Related Figures: 11-26. Part Terminology: Wind Turbine (1), VIASAD/VIFSAD device (2) , Wind (3) .

Description: The Off—the-Rotor variant of a VIASAD/VIFSAD device is attached to a single wind turbine. The device is preferably attached to the turbine nacelle, so that it is aligned with the incoming flow at all times. The suction or secondary flow generated, drives the Active/Laminar Flow Control on the rotor blades. (Note: The size of the VIASAD/VIFSAD device is a little bit exaggerated here) .

[0047] FIGURE: 17. A 3D View of an Off-the-Rotor version of a VIASAD/VIFSAD device used as an Adverse Pressure Gradient suppressor on the rotating blades of a wind turbine. Related Figures: 11 to 26. Part Terminology: Wind (1), Wind Turbine tower (2), VIASAD/VIFSAD device (3), Primary Suction flow (4), Suction tube with Secondary flow (5), Wind Turbine nacelle (6), Suction on the blade surface to suppress adverse pressure gradients (7), Wind Turbine blade (8). Description: The Primary flow in the VIASAD/VIFSAD device generates suction which in turn drives the Secondary flow. The secondary flow is used to suck the stall bubble or suppress the adverse pressure gradients from the surface of the Wind Turbine blades.

[0048] FIGURE: 18. A Stand-Alone version of a VIASAD/VIFSAD device driving Active Flow Control on multiple wind turbines. Related Figures: 11-26.

Part Terminology: Wind Turbine (1), VIASAD/VIFSAD device (2) . Description: The VIASAD/VIFSAD device is supporting multiple wind turbines or a whole wind farm. The suction or secondary flow that is generated by the VIASAD/VIFSAD device, drives the Active/Laminar Flow Control on the rotor blades of the wind turbines. [0049] FIGURE: 19. Offshore Wind Turbine coupled with Stand- Alone VIASAD/VIFSAD device variant, which operates with underwater currents. Related Figures: 11-26. Part Terminology: Underwater current (1), Water surface (2), VIASAD/VIFSAD device (3), Suction Flow - Secondary Flow (4), Wind (5), Tower base (6), Wind Turbine blade (7), Wind Turbine Tower (8), Wind Turbine nacelle (9). Description: The VIASAD/VIFSAD device generates suction (low pressure) by the use of underwater currents. This is used to suck the slow moving air in the boundary layer on the low- pressure surface of the rotor blades (BLS = Boundary Layer Suction) . As a result the flow remains attached even at high angles of attack and also transition to turbulent flow is delayed by enhancing the laminar flow. This improves the Lift to Drag (L/D) ratio and ultimately the aerodynamic performance of the blade is improved.

[0050] Figure : 20. Wind Turbine Rotor Blade with APG suppressor suction Holes.

Related Figures: 21, 22, 23, 24, 25A/B.

Part Terminology: Blade Leading Edge (1), Rotor Hub (2), Suction Holes - APG suppressor (3), Blade Trailing Edge (4), Wind Turbine Blade (5) . Description: Using the Suction generated by a VIASAD/VIFSAD or JETIASAD/JETIFSAD device, slow-moving air is sucked through the APG suppressor holes on the blade. As a result the flow stays attached and smooth at higher angles of attack, increasing the blade' s lift coefficient and hence enhancing its performance.

[0051] Figure : 21. Wind Turbine Rotor Blade with APG suppressor trailing edge suction inlet. Related Figures: 20, 22, 23, 24, 25A/B. Part Terminology: Blade Leading Edge (1), Rotor Hub (2), Suction Inlet - APG suppressor (3), Blade Trailing Edge (4), Wind Turbine Blade (5) .

Description: Using the Suction generated by a VIASAD/VIFSAD or JETIASAD/JETIFSAD device, slow-moving air is sucked through the trailing edge inlet of the APG suppressor. As a result the flow stays attached and smooth at higher angles of attack, increasing the blade's lift coefficient and hence enhancing its performance.

[0052] Figure : 22. Wind Turbine Rotor Blade with APG suppressor trailing edge suction vanes. Related Figures: 20, 21, 23, 24, 25A/B.

Part Terminology: Blade Leading Edge (1), Rotor Hub (2), Suction Vanes - APG suppressor (3), Blade Trailing Edge (4), Wind Turbine Blade (5) .

Description: Using the Suction generated by a VIASAD/VIFSAD or JETIASAD/JETIFSAD device, slow-moving air is sucked through the trailing edge vanes of the APG suppressor. As a result the flow stays attached and smooth at higher angles of attack, increasing the blade's lift coefficient and hence enhancing its performance.

[0053] FIGURE: 23. 3D Flow over a Wind Turbine blade when in stall. Related Figures: 12 to 25A/B.

Part Terminology: Blade tip (1), Relative Wind Flow (2), Blade Leading Edge (3), Secondary or Suction Flow (4), Inflow from the root of the blade (5), Stall bubble (6). Description: A rotating wind turbine blade at high angle of attack experiences stall. Strong adverse pressure gradients give rise to reverse flow which ultimately results in the creation of a bubble. Stall leads to rapid decrease of lift and increase of drag which result in degradation of the output performance of the wind turbine. So, when the wind turbine is operating in the power-extraction mode it is desirable to suppress stall. A VIASAD/VIFSAD device is doing just that: suppressing the generated stall on the rotating wind turbine blades .

[0054] FIGURE: 24. 2D Flow over an airfoil section of a Wind Turbine blade with stall bubble suction. Related Figures: 12 to 25A/B.

Part Terminology: Stall Bubble or Reverse Flow (1), Airfoil Section (2), Suction Tube (3), Secondary or Suction Flow (4) . Description: A rotating wind turbine blade at high angle of attack experiences stall. Strong adverse pressure gradients give rise to reverse flow which ultimately results in the creation of a bubble. Stall leads to rapid decrease of lift and increase of drag which result in degradation of the output performance of the wind turbine. So, when the wind turbine is operating in the power-extraction mode it is desirable to suppress stall. A VIASAD/VIFSAD device is doing just that: suppressing the generated stall on the rotating wind turbine blades .

[0055] Figure : 25A. Wind Turbine Blade airfoil section with suction flow generated by a VIASAD/VIFSAD APG suppressor device . Related Figures: 11-24. Part Terminology: Air Flow over the Blade (1), Suction Inlet opening (2), Suction Inlet - APG suppressor (3), Blade Trailing Edge (4), Hinge (5), Suction Flow (6), Blade Airfoil Section (7), Suction Tube (8), Blade Leading Edge (9). Description: Slow moving air is sucked through the trailing edge inlet of the APG suppressor. As a result the flow stays attached and smooth at higher angles of attack, increasing the blade's lift coefficient and hence enhancing its performance.

[0056] Figure : 25B. Wind Turbine Blade airfoil section with suction flow generated by a VIASAD/VIFSAD APG suppressor device .

Related Figures: 11-24.

Part Terminology: Air Flow over the Blade (1), Suction Flow through the APG holes (2), Blade Trailing Edge (3), Suction

Flow (4), Suction Tube (5), Blade Leading Edge (6).

Description: Slow moving air is sucked through the suction holes of the APG suppressor. As a result the flow stays attached and smooth at higher angles of attack, increasing the blade's lift coefficient and hence enhancing its performance.

[0057] Figure: 26. VIASAD/VIFSAD Functional Principles. Related Figures: 11, 12, 13. Description: The VIASAD/VIFSAD mechanism is a device that utilizes low-energy density fluid flow, which is readily available in nature, and converts it to high-energy density flow structures like vortices, which can be efficiently used to improve the aerodynamic characteristics of wind/air/water turbines, resulting in enhancing their power output. Effectively, the displayed mechanism attempts to imitate the basic principles behind Aquatic Locomotion and maneuvering as well as Flight Propulsion, in which energy is efficiently harnessed as it is transformed from one form to the other.

[0058] Figure: 27. Wind Turbine with no VIASAD/VIFSAD device installed.

Related Figures: 14, 28.

Description: This diagram illustrates the contribution of different parts of the rotating blades to the power output of a wind turbine. As shown by the smaller arrows on the blade, the inner part of the blade (2/3 from the root) contributes a lot less than the outer part (1/3 at the tip) . Basically, the aerodynamic forces developed on the blade part close to the root, due to their relative short distance from the pivot or rotor hub, are not effective in generating torque and as a result they are not contributing a lot to the power output of the turbine. On the other hand, the aerodynamic forces at the blade tip, contribute most of the generated torque and hence power output of the turbine. This explains the logic behind using a VIASAD/VIFSAD device integrated at the rotor hub of a turbine. The VIFSAD device harnesses energy from the hub of the turbine and redirects it to the blade tips, where it can be used more effectively in generating power output.

[0059] Figure: 28. Wind Turbine a VIASAD/VIFSAD device integrated at its rotor hub. Related Figures: 14, 27.

Description: This diagram illustrates the redirection of the energy harnessed at and around the rotor hub to the tips of the rotating blades. The result is an enhanced aerodynamic force at the tips which gives rise to augmented generated torque and hence higher power output. The aerodynamic force at the tips is represented by two arrows: One is the normally created force and the second arrow is the extra force generated due to the redirection of harnessed energy from the rotor hub to the tips. If this extra force was applied at the inner part of the blade then its contribution to the overall power output of the turbine would have been a lot less.

Claims

1. VIASAD/VIFSAD : Vortex Induced Air/Flow Speed Amplification Device. (Figures 11, 12, 13, 26) VIASAD is a pressure differential device which compresses incoming air flow from the wind or underwater currents and directs the resulting accelerated flow past vortex generators to generate a system or pattern of air/water vortices, of ANY TYPE or CONFIGURATION. The generated air/water vortices induce a suction effect. Generally, a VIASAD/VIFSAD device is a mechanism for transforming a low energy density flow into a high energy density vortical flow pattern which can be efficiently used by energy consuming devices. It consists of the following parts: (1) Contraction or Converging nozzle.

The purpose of this part is to accelerate the incoming air/water flow from the wind/underwater currents by contracting or compressing it. The intake of the contraction is facing the wind/underwater currents.

The ratio of the Intake to the Exhaust Area (Ain/Aout) is optimized to achieve maximum acceleration of air/water inflow. The contracting walls can take various shapes and they are not limited to only one shape (Fig5D/E) . The goal here is to minimize friction losses and keep boundary layer as thin as possible .

The contraction of the nozzle walls can take different forms: It might be 1-D along the direction of the incoming flow, either on the vertical plane or on the horizontal plane. It might also be 2-D and thus the contraction takes place on both the horizontal and vertical planes. Or the contraction can be multi-D like for example the case of a venturi tube where the contraction takes place on all radially-arranged planes along the direction of the wind/underwater current. (2) Vortex Generators. The purpose of this part is to generate a system or pattern of air/water vortices of ANY TYPE or CONFIGURATION. The geometrical shape of the vortex generators can take ANY FORM in order to maximize its performance for their intended purpose.

ALL different types of vortex generators can be used. Some of the options are the following:

Fences or walls or grooves or extrusions or lifting bodies placed at different angles of attack to the air flow. They can be located inside the converging nozzle, but they can also extend outside from both the inlet and outlet of the nozzle.

(3) Vortex Lateral Expansion Chamber/Area.

The purpose of this part is to allow the lateral expansion of the generated vortices in a controllable way. It is basically a closed area which gives space to the generated vortices to expand laterally as they propagate towards the exhaust nozzle of the VIASAD/VIFSAD pressure differential device.

(4) Vortex Lateral Contraction Mechanism - Low Pressure Region The purpose of this part is to accelerate the vortical flow by laterally contracting the generated vortices (On a plane perpendicular to the direction of propagation) . It can be either of variable geometry or fixed geometry. It can take many different forms. Two options are the following: Moving flaps/surfaces or converging nozzles of any geometry. (5) Air/Water Suction Tube/Channel.

The purpose of this part is to efficiently guide the air flow (Air/Wind Turbine) or the water flow (Water/Underwater current Turbine) induced by suction, into the low pressure region of the VIASAD/VIFSAD device. The low-pressure region is where the generated vortices along with the high-speed jet stream are compressed and thus inducing the suction effect. The Air/Water Suction Tube communicates with the low pressure region via a system of holes, slots and/or vanes (openings) . These openings exist on the walls of the Vortex Lateral Contraction Mechanism or the walls of the low pressure region. This region is between the vortex lateral expansion chamber and the diffusion nozzle. (6) Diffusion or Exhaust Nozzle.

The purpose of this part is to allow for the gradual expansion of the accelerated flow (jet stream and vortices) and hence minimize pressure losses for the generated suction. The operation of the VIASAD/VIFSAD device is characterized by two types of flows:

A. Primary Flow. It can be either Air/Wind Flow or water/Underwater Current Flow.

B. Secondary Flow. It is the Air Flow induced by suction generated in the Primary Flow.

Primary Flow The Primary Flow consists of the following multiple stages:

Stage 1: Use of a contraction or a converging nozzle in order to accelerate the incoming wind/water flow.

Stage 2: Produce a pattern of high-speed vortices by the use of vortex generators. The air/water flow accelerated in stage 1 is guided past vortex generators.

Stage 3: Allow the generated vortices to expand laterally.

Stage 4: Generate suction by restricting the flow path of the generated high-speed vortices.

Stage 5: Diffusion or expansion of the accelerated air/water flow and the generated vortices through a diverging nozzle.

Secondary Flow

It can only exist in tandem with the Primary Flow. It is the result of suction generated in the Primary Flow.

It constitutes the useful energy output of the VIASAD/VIFSAD Device .

2. An Air/Water Turbine with a fan or an impeller or a rotor of ANY TYPE or CONFIGURATION (Axial or Centrifugal) which is enclosed in a casing and it is primarily driven by Suction Air/Water Flow induced by the use of the mechanism claimed in Claim 1:

VIASAD/VIFSAD : Vortex Induced Air/Flow Speed Amplification

Device. (Figures 4A/B/C, 5A/B/C/D/E, 6, 7, 8, 9, 10)

The Air/Water Turbine consists of the following parts:

(1) VIASAD/VIFSAD Device. The purpose of this part is to generate suction which drives air/water flow through a casing or housing enclosing the air/wind/water turbine fan/impeller.

(2) Fan Casing or Housing.

This part encloses or covers the fan/impeller of the air/wind/water turbine.

The purpose of this part is to efficiently guide the incoming air/water flow through the blades of the air/wind/water turbine fan/impeller and ultimately release the air/water through discharge openings/outlets into the Air/Water Suction Tubes of the VIASAD device.

(3) Rotor or Fan or Impeller.

The Fan/Impeller can be Axial or Centrifugal or an Impeller/Propeller of ANY TYPE or CONFIGURATION with ANY number of blades which will best serve its intended purpose by maximizing its output performance. Its output performance is measured as the ratio of the output power delivered through a shaft to the input power content of the incoming air/water flow (Primary Flow) .

(4) Rotor Shaft. This part is used to deliver the output power developed by the air/wind/water turbine rotor to an outside power consuming device or a generator.

(5) Rotor Air Flow Exhaust Tubes.

They are used for guiding the air/water outflow from the rotor casing into the Air/Water Suction Tubes connecting to the VIASAD device. (6) Rotor Casing Exhaust Outlets.

They constitute air/water flow communication gateways between the rotor casing and the exhaust tubes. (7) Air/Wind/Water Turbine Yaw Control Mechanism.

A mechanism used for directing the intakes of the converging nozzles of the VIASAD/VIFSAD device as well as the intake of the rotor casing towards the wind. (8) Air/Wind/Water Turbine Tower. This a structure that supports the whole air/wind/water turbine at a certain height above the ground at the site where it is installed.

The functionality of the proposed air/wind/water turbine consists of the following series of main stages: Stage 1 : Accelerate the incoming wind/water/water flow

(Primary Flow) .

Stage 2: Generate high-speed air/water vortices. Stage 3: Give rise to a suction effect as a result of the generated pattern of high-speed air/water jet streams along with high-speed air/water vortices.

Stage 4: Make use of the low pressure suction effect to induce or drive an artificially generated high-speed air/water flow (Secondary Flow) through the blades of the air/wind/water turbine rotor or fan. The air/water flow through the rotor blades has a lot higher concentration of power per unit volume than the Wind/Underwater Current .

Fundamentally, the air/wind/water turbine is using the VIASAD/VIFSAD device to compress the energy content of the incoming wind or underwater current (Primary Flow) , in order to induce by suction an air/water flow (Secondary Flow) with highly concentrated energy content which is ultimately used to efficiently drive the air/wind/water turbine rotor.

3. VIASAD/VIFSAD - APG suppressor: Adverse Pressure Gradient suppressor. (Figures 11 through 25)

It consists of a combination of a VIASAD/VIFSAD device claimed in claim 1, with a system of air/water suction pipes/ducts or channels and a suction porous area on the outer skin of the surface of the wings/lifting surfaces of air/wind/water turbine rotor blades.

The suction generated by the VIASAD/VIFSAD device is used to suppress adverse pressure gradients of the flow close to the surface of wings or rotor blades or other lifting surfaces used by Wind / Air / Underwater Turbines . The slow-moving air/water close to the surface of the wings/blades is sucked through different types of porous openings that lead to air/water pipes or ducts which are ultimately connected to the low-pressure region of the VIASAD/VIFSAD device. These porous openings or holes or slots or vanes can have ANY type of SHAPE and CONFIGURATION and they can be arranged in ANY type of PATTERN that will serve their purpose best. The flow-rate of the air/water suction through the porous surface can vary by adjusting the number of holes that are open at any time or by restricting the air flow through the suction channels or otherwise. A feedback control system can be used for this purpose. This claim is characterized by higher lift coefficients, enhanced lift over a wider range of angles of attack, delayed stall, reduced drag coefficients and higher

Lift-to-Drag ratio (L/D) of the wings/blades. This is a direct consequence of the suction of slow-moving air/water which suppresses the adverse pressure gradients close to the surface of the wings/blades.

4. Pressure Differential Device - APG suppressor. (Figures 14 through 25)

It consists of a combination of any type of a Pressure Differential Device generating suction (other than the one claimed in Claim 1), with a system of air/water suction pipes/ducts or channels and a suction porous area on the outer skin of the surface of the wings/lifting surfaces or air/wind/water turbine rotor blades. The Pressure Differential Device can be any mechanism which uses a single or multiple converging nozzles of ANY TYPE or

CONFIGURATION and arranged in ANY PATTERN in order to compress and thus accelerate the incoming wind/air/underwater current. One example of such pressure differential device is a Venturi tube. The suction generated by the Pressure Differential Device is used to suppress adverse pressure gradients of the flow close to the surface of wings or rotor blades or other lifting surfaces used by Wind / Air / Underwater Turbines. The slow-moving air/water close to the surface of the wings/blades is sucked through different types of porous openings that lead to air/water pipes or ducts which are ultimately connected to the low-pressure region of the pressure differential device. These porous openings or holes or slots or vanes can have ANY type of SHAPE and CONFIGURATION and they can be arranged in ANY type of PATTERN that will serve their purpose best. The flow-rate of the air/water suction through the porous surface can vary by adjusting the number of holes that are open at any time or by restricting the air/water flow through the suction channels or otherwise. A feedback control system can be used for this purpose. This claim is characterized by higher lift coefficients, enhanced lift over a wider range of angles of attack, delayed stall and reduced drag coefficients of the wings/blades. This is a direct consequence of the suction of slow-moving air/water which suppresses the adverse pressure gradients close to the surface of the wings/blades.

5. VIASAD/VIFSAD APG suppressor - Air/Wind/Underwater Current Turbine operated at wind/Underwater current speeds below its rated wind/underwater current speed. (Figures 11 through 25) The secondary flow generated by suction in a VIASAD/VIFSAD APG suppressor device, claimed in Claim 3, is used for suppressing stall on the blades of an Air/Wind Turbine operated at wind speeds below its rated wind speed (maximum power output) . The suppression of stall allows the operation of an Air/Wind Turbine with its blades at higher than normal angles of attack. This is achieved by having the secondary/suction flow suppressing the stall bubble as well as adverse pressure gradients on the surface of the blade and as a result the flow remains attached. This contributes to the increase of the Lift Coefficient and at the same time the decrease of the corresponding Drag Coefficient. Consequently the Lift-to-Drag ratio (L/D) is enhanced which effectively means higher generated torque and as result the output performance of the Air/Wind Turbine is improved. In a similar way, an underwater current turbine can improve its output performance by having a VIASAD/VIFSAD APG suppressor device suppress its stall when its blades are at high angle of attack.

6. VIASAD/VIFSAD APG suppressor - Stalled Controlled Air/Wind/Underwater Current Turbine operated at wind/Underwater current speeds above its rated wind/underwater current speed. (Figures 11 through 25) The secondary flow generated by suction in a VIASAD/VIFSAD APG suppressor device, claimed in Claim 3, is used for controlling stall on the blades of an Air/Wind Turbine operated at wind speeds above its rated wind speed (maximum power output) . The stall control is done in order to achieve the following: Make the separated area or the stall bubble on the blades extend in such a way, that the extracted power remains relatively constant (stabilizes), independent of the wind speed, while the power available in the wind at cut-out (Operation stops) exceeds the maximum power output of the turbine by a certain factor. Currently for commercially available, utility size wind turbines, this factor has an optimum value between 8 and 10. In order to achieve the above, a feedback control system will have to be used to adjust the flow rate of the secondary/suction flow continuously. In a similar way, an underwater current turbine can be stall-controlled by having a VIASAD/VIFSAD APG suppressor device control/suppress its stall when the underwater current speed exceeds the rated value for the turbine.

7. VIASAD/VIFSAD APG suppressor - Application of Laminar Flow Control (LFC) and/or Hybrid Laminar Flow Control (HLFC) on the blades/lifting surfaces of an Air/Wind/Underwater Current Turbine. (Figures 11 through 25) Use of a VIASAD/VIFSAD APG suppressor claimed in Claim 3 for applying Laminar Flow Control (LFC) or Hybrid Laminar Flow Control (HLFC) in order to minimize skin-friction and pressure drag of the rotating/moving wind turbine blades/lifting surfaces. Basically, use the secondary/suction flow generated by a VIASAD/VIFSAD APG suppressor claimed in Claim 3, in order to apply suction, suppress the adverse pressure gradients and keep the flow over the blade/wing/lifting surface laminar and delay transition to turbulence. The Laminarization of the flow results in lower overall drag and smooth and attached air flow at higher angle of attack, which effectively gives higher Lift and lower Drag. In a similar way, a VIASAD/VIFSAD APG suppressor can be used to generate suction flow which is ultimately used for applying LFC and HLFC on the blades/lifting surfaces of an underwater current turbine.

8. Pressure Differential Device APG suppressor -

Air/Wind/Underwater Current Turbine operated at wind/Underwater current speeds below its rated wind/underwater current speed. (Figures 14 through 25) The secondary flow generated by suction in a Pressure

Differential Device APG suppressor, claimed in Claim 4, is used for suppressing stall on the blades of an Air/Wind Turbine operated at wind speeds below its rated wind speed (maximum power output) . The suppression of stall allows the operation of an Air/Wind Turbine with its blades at higher than normal angles of attack. This is achieved by having the secondary/suction flow suppressing the stall bubble as well as adverse pressure gradients on the surface of the blade and as a result the flow remains attached. This contributes to the increase of the Lift Coefficient and at the same time the decrease of the corresponding Drag Coefficient. Consequently the Lift-to-Drag ratio (L/D) is enhanced which effectively means higher generated torque and as result the output performance of the Air/Wind Turbine is improved. In a similar way, an underwater current turbine can improve its output performance by having a Pressure Differential Device APG suppressor suppress its stall when its blades are at high angle of attack.

9. Pressure Differential Device APG suppressor - Stalled Controlled Air/Wind/Underwater Current Turbine operated at wind/Underwater current speeds above its rated wind/underwater current speed. (Figures 14 through 25) The secondary flow generated by suction in a Pressure

Differential Device APG suppressor, claimed in Claim 4, is used for controlling stall on the blades of an Air/Wind Turbine operated at wind speeds above its rated wind speed (maximum power output) . The stall control is done in order to achieve the following: Make the separated area or the stall bubble on the blades extend in such a way, that the extracted power remains precisely constant, independent of the wind speed, while the power available in the wind at cut-out (Operation stops) exceeds the maximum power output of the turbine by a certain factor. Currently for commercially available, utility size wind turbines, this factor has an optimum value between 8 and 10. In order to achieve the above, a feedback control system will have to be used to adjust the flow rate of the secondary/suction flow continuously. In a similar way, an underwater current turbine can be stall- controlled by having a Pressure Differential Device APG suppressor control/suppress its stall when the underwater current speed exceeds the rated value for the turbine.

10. Pressure Differential Device APG suppressor - Application of Laminar Flow Control (LFC) and/or Hybrid Laminar Flow Control (HLFC) on the blades/lifting surfaces of an Air/Wind/Underwater Current Turbine. (Figures 14 through 25) Use of a Pressure Differential Device APG suppressor claimed in Claim 4, for applying Laminar Flow Control (LFC) or Hybrid Laminar Flow Control (HLFC) in order to minimize skin-friction and pressure drag of the rotating/moving wind turbine blades/lifting surfaces. Basically, use the secondary/suction flow generated by a Pressure Differential Device APG suppressor claimed in Claim 4, in order to apply suction, suppress the adverse pressure gradients and keep the flow over the blade/wing/lifting surface laminar and delay transition to turbulence. The Laminarization of the flow results in lower overall drag and smooth and attached air flow at higher angle of attack, which effectively gives higher Lift and lower Drag. In a similar way, a Pressure Differential Device APG suppressor can be used to generate suction flow which is ultimately used for applying LFC and HLFC on the blades/lifting surfaces of an underwater current turbine.

11. VIASAD/VIFSAD APG suppressor - Suppression/Control of Stall on an Oscillating Wing.

It consists of the VIASAD/VIFSAD device claimed in Claim 1 and a variant of the Adverse Pressure Gradient suppressor claimed in Claim 3, installed on an oscillating wing. When the oscillating wing is operated in the power-extraction mode, the VIASAD/VIFSAD APG suppressor is used to suppress stall in order to enhance output performance. It is characterized by a system of holes/slots on both of its top and bottom surfaces. The holes on each surface (bottom/top) open intermittently to allow the suction of slow-moving air based on the direction of movement of the oscillating wing:

1. Oscillating wing moving Up: Compression and hence pressure drop occurs on the top surface of the wing. Holes on the top surface open up and those on the bottom surface are closed.

2. Oscillating wing moving Down: Compression and hence pressure drop occurs on the bottom surface of the wing. Holes on the bottom surface open up and those on the top surface are closed.

A VIASAD/VIFSAD device is used to suck slow-moving air through this system of holes/slots. The holes/slots can have ANY type of SHAPE, and they can be arranged in ANY type of PATTERN on each surface of the oscillating wing. The suction air flow- rate can vary by using a feedback control system to adjust the number of holes that are open at any time or by restricting the air flow through the suction channels.

12. Pressure Differential Device APG suppressor - Suppression/Control of Stall on an Oscillating Wing. It consists of a variant of the Pressure Differential Device APG suppressor claimed in Claim 4, installed on an oscillating wing. When the oscillating wing is operated in the power- extraction mode, the Pressure Differential Device APG suppressor is used to suppress stall in order to enhance output performance. It is characterized by a system of holes/slots on both of its top and bottom surfaces. The holes on each surface (bottom/top) open intermittently to allow the suction of slow-moving air based on the direction of movement of the oscillating wing:

A Pressure Differential Device APG suppressor is used to suck slow-moving air through this system of holes/slots. The holes/slots can have ANY type of SHAPE, and they can be arranged in ANY type of PATTERN on each surface of the oscillating wing. The suction air flow-rate can vary by using a feedback control system to adjust the number of holes that are open at any time or by restricting the air flow through the suction channels.

13. VIASAD/VIFSAD APG suppressor - Application of Laminar Flow Control (LFC) and/or Hybrid Laminar Flow Control (HLFC) on an Oscillating Wing. Use of a VIASAD/VIFSAD APG suppressor claimed in Claim 3 for applying Laminar Flow Control (LFC) or Hybrid Laminar Flow

Control (HLFC) in order to minimize skin-friction and pressure drag of an oscillating wing. Basically, use the secondary/suction flow generated by a VIASAD/VIFSAD APG suppressor device claimed in Claim 3, in order to apply suction, suppress the adverse pressure gradients and keep the flow over the oscillating wing surface laminar and delay transition to turbulence. The Laminarization of the flow results in lower overall drag and smooth and attached air flow at higher angle of attack, which effectively gives higher Lift and lower Drag. In a similar way, a VIASAD/VIFSAD APG suppressor can be used to generate suction flow, which is ultimately used for applying LFC and HLFC on the surface of an underwater Oscillating wing.

14. Pressure Differential Device APG suppressor - Application of Laminar Flow Control (LFC) and/or Hybrid Laminar Flow Control (HLFC) on an Oscillating Wing. Use of a Pressure Differential Device APG suppressor claimed in Claim 4, for applying Laminar Flow Control (LFC) or Hybrid Laminar Flow Control (HLFC) in order to minimize skin-friction and pressure drag of an oscillating wing. Basically, use the secondary/suction flow generated by a Pressure Differential Device APG suppressor claimed in Claim 4, in order to apply suction, suppress the adverse pressure gradients and keep the flow over the oscillating wing surface laminar and delay transition to turbulence. The Laminarization of the flow results in lower overall drag and smooth and attached air flow at higher angle of attack, which effectively gives higher Lift and lower Drag.

In a similar way, a Pressure Differential Device APG suppressor can be used to generate suction flow which is ultimately used for applying LFC and HLFC on the surface of an underwater Oscillating wing.

15. VIASAD/VIFSAD APG suppressor - Rotor Hub Variant. (Figures 13, 14, 28)

A VIASAD/VIFSAD device claimed in Claim 1, or a VIASAD/VIFSAD APG Suppressor device claimed in Claim 3, is installed or integrated into the rotor hub of a Wind / Air / Water Turbine along the axis of rotation of the rotor. This configuration of the VIASAD/VIFSAD device and a turbine, has the advantage of redirecting the incoming flow harnessed at the hub of the turbine, to the tips of the rotor blades, where the flow energy can be used more effectively to generate torque and hence power output. (Figures 27, 28)

The rotor hub variant of the VIASAD/VIFSAD APG Suppressor device is characterized by a cross sectional area the size of which is optimized so that power output performance of the turbine is not negatively affected. The suction generated by the VIASAD/VIFSAD device at the rotor hub is used to achieve the following:

(1) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow on the rotating blades of the turbine. (2) Suppress, stabilize or prevent the separation bubble from developing at the low-pressure surface of the rotating blades. This variant of the device integrated into the rotor hub, can take ANY shape or configuration in order to accommodate its integration with the rotor in the best possible way. The design of this variant is based on the design principles of the VIASAD/VIFSAD - APG suppressor device claimed in Claims 1 and 3. A recommended configuration, but it's not restricted to, is the following: It primarily consists of 2 parts: (1) A Cylinder and (2) A Core.

One of these parts (The Cylinder or the Core) can be rotating while the other part is stationary. Or both parts can be rotating in sync. Or they can be counter-rotating to each other. The most important feature of this configuration is the shape of the core: Its frontal part facing the wind / air / water inflow can have a conical or spherical shape in order to form along with the cylinder, a contraction which compresses and accelerates the incoming flow. The incoming flow moves outwards from the center of rotation and towards the walls of the outer cylinder where a gap is formed between the cylinder and the core. The next part of the core, consists of a cylindrical slice with constant diameter which forms with the outer cylinder a channel of constant cross-sectional area. Next, the core has a converging shape towards the axis of rotation, in order to allow enough space for the generated vortices to expand laterally. The part of the core that follows, forms the Vortex Lateral Contraction Mechanism: This part of the core is responsible for harnessing the energy from the generated vortices by compressing them and hence giving rise to suction. It consists of one or multiple pieces. The shape of each one of these pieces expands away from the axis of rotation (in the same or various degrees), and in this way, it compresses the generated vortices flowing outwards. The Vortex Lateral Contraction Mechanism can have its constituent pieces sliding or moving in any possible way, so as to vary the cross-sectional area of the vortex exit path. The varying area of the exit nozzle helps to maximize the generated suction depending on the strength of the generated vortices. Eventually the accelerated vortical flow goes through the last part of the core, which forms a diffusion nozzle along with the outer cylinder part.

As dictated by the main design principles of the VIASAD/VIFSAD device claimed in Claim 1, the accelerated incoming flow is converted to vortical flow by the use of vortex generators. These vortex generators can have ANY shape or configuration and be arranged in ANY possible pattern, which will serve their purpose best. They can be arranged on the core, or the inside surface of the cylinder or on both parts. The device has two low-pressure regions: One at the front where the inflow is initially compressed and one at the rear where the generated vortical flow is compressed. These low-pressure or suction regions are connected via tubes and channels to porous surfaces located on the skin of the rotating rotor blades. The porous surfaces consist of holes or inlet vanes or any type of openings, through which separated or decelerated flow is sucked away from the blade surface. As a result the aerodynamic characteristics of the rotating blades are augmented or improved. It is important to note that the outer shell of the recommended variant device of this Claim, can have any shape other than being a cylinder. For example, it can be a diverging truncated cone (smaller inlet facing the inflow) joined to a converging truncated cone. The main goal is to implement the basic design principles of a VIASAD/VIFSAD device: Converging Nozzle, Diverging Nozzle, Converging Nozzle, Diffusion Nozzle.

16. VIASAD/VIFSAD APG suppressor - Off the Rotor Variant. (Figures 15,16,17)

A VIASAD/VIFSAD device claimed in Claim 1, or a VIASAD/VIFSAD APG Suppressor device claimed in Claim 3, is coupled or installed on a Wind / Air / Water Turbine. The inlet of the device is positioned outside the turbine rotor area so that the incoming flow is unobstructed by the rotating blades. The energy harnessed by the VIASAD/VIFSAD device is used to augment the aerodynamic characteristics of the rotating rotor blades, preferably at the tip, and hence increase the turbine output performance.

Specifically, the suction generated by the VIASAD/VIFSAD device is used to achieve the following: (1) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow on the rotating blades of the turbine. (2) Suppress, stabilize or prevent the separation bubble from developing on the low-pressure surface of the rotating blades.

17. VIASAD/VIFSAD APG suppressor - Stand Alone Variant. (Figure 18)

A VIASAD/VIFSAD device claimed in Claim 1, or a VIASAD/VIFSAD APG Suppressor device claimed in Claim 3, is independently or separately installed on its own tower or installation structure. The energy harnessed by the VIASAD/VIFSAD device is used to improve the power output of one or multiple wind / air / water turbines. This is achieved by using the suction generated by the VIASAD/VIFSAD device in order to augment the aerodynamic characteristics of the rotating rotor blades, preferably at the tip, and hence increase the turbine output performance .

18. Pressure Differential Device APG suppressor - Rotor Hub Variant. (Figures 13, 14)

A Pressure Differential device APG Suppressor claimed in Claim 4, is installed or integrated into the rotor hub of a Wind / Air / Water Turbine along the axis of rotation of the rotor. This configuration of the Pressure Differential Device and a turbine, has the advantage of redirecting the incoming flow harnessed at the hub of the turbine, to the tips of the rotor blades, where the flow energy can be used more effectively to generate torque and hence power output.

The rotor hub variant of the Pressure Differential Device - APG Suppressor is characterized by a cross sectional area the size of which is optimized so that power output performance of the turbine is not negatively affected. The energy harnessed by the Pressure Differential device installed at the hub is used to augment the aerodynamic characteristics of the rotating rotor blades, preferably at the tip, and hence increase the turbine output performance. Specifically, the suction generated by the Pressure Differential device at the rotor hub is used to achieve the following: (1) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow on the rotating blades of the turbine. (2) Suppress, stabilize or prevent the separation bubble from developing at the low-pressure surface of the rotating blades.

19. Pressure Differential Device APG suppressor - Off the Rotor Variant. (Figures 15, 16, 17)

A Pressure Differential device APG Suppressor claimed in Claim 4, is coupled or installed on a Wind / Air / Water Turbine. The inlet of the device is positioned outside the turbine rotor area so that the incoming flow is unobstructed by the rotating blades. The energy harnessed by the Pressure Differential device is used to augment the aerodynamic characteristics of the rotating rotor blades, preferably at the tip, and hence increase the turbine output performance. Specifically, the suction generated by the Pressure Differential device is used to achieve the following: (1) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow on the rotating blades of the turbine. (2) Suppress, stabilize or prevent the separation bubble from developing on the low- pressure surface of the rotating blades.

20. Pressure Differential Device APG suppressor - Stand Alone Variant. (Figure 18)

A Pressure Differential device claimed in Claim 4, is independently or separately installed on its own tower or installation structure. The energy harnessed by the Pressure Differential device is used to improve the power output of one or multiple wind / air / water turbines. This is achieved by using the suction generated by the Pressure Differential device in order to augment the aerodynamic characteristics of the rotating rotor blades, preferably at the tip, and hence increase the turbine output performance. Specifically, the suction generated by the Pressure Differential device is used to achieve the following: (1) Apply Laminar Flow Control (LFC) or Hybrid Laminar Flow on the rotating blades of the turbine. (2) Suppress, stabilize or prevent the separation bubble from developing on the low- pressure surface of the rotating blades.

21. Vorticity Passive/Active Control (VoPAC) Pressure Differential Device.

This is a more general version of the Pressure Differential device claimed in Claim 1. It is characterized by the same design principles as VIASAD/VIFSAD claimed in Claim 1. However, the harnessing of the energy possessed by the generated vorticity can be done both passively and/or actively. Effectively, VoPAC Pressure Differential device uses either a passive or an active mechanism or both, in order to intercept the generated vortices, and extract their energy content, which is ultimately converted to suction. The vorticity passive control mechanism used by the device claimed in this claim, can take ANY form or shape or configuration. Examples of such configurations are the following: A wing, a flap or a truncated cone or a combination of all these, and in any pattern or multiplicity. As indicated by its name, this mechanism passively intercepts and compresses the generated vorticity . The vorticity active control mechanism claimed in this claim, alone or in combination with the passive control mechanism, responds to a feedback control system, which synchronizes the reaction of a system or pattern of control surfaces with the generated vortices. The mode of interaction between the control surfaces and the generated vorticity, is optimized in such a way, so that the compression of the vortices maximizes the achieved suction. The control surfaces used, can take ANY shape and they can be rigid or flexible (in the form of a membrane) . The active control mechanism, can take ANY form or configuration and it can be oscillating, sliding or moving in any possible way in order to maximize the generated suction. Both the vorticity passive and active control mechanisms that characterize this claim, imitate the vorticity control in fish- like propulsion and maneuvering or the thrust enhancement of birds flying in formations.

22. VoPAC Pressure Differential Device - APG suppressor: Adverse Pressure Gradient suppressor.

It consists of a combination of a VoPAC pressure differential device claimed in claim 21, with a system of air/water suction pipes/ducts or channels and a suction porous area on the outer skin of the surface of the wings/lifting surfaces of an air/wind/water turbine rotor blades.

The suction generated by the VoPAC device is used to suppress adverse pressure gradients of the flow close to the surface of wings or rotor blades or other lifting surfaces used by Wind / Air / Underwater Turbines. The slow-moving air/water close to the surface of the wings/blades is sucked through different types of porous openings that lead to air/water pipes or ducts, which are ultimately connected to the suction region of the VoPAC device. These porous openings or holes or slots or vanes can have ANY type of SHAPE and CONFIGURATION and they can be arranged in ANY type of PATTERN that will serve their purpose best. The flow-rate of the air/water suction through the porous surface can vary by adjusting the number of holes that are open at any time or by restricting the air flow through the suction channels or otherwise. A feedback control system can be used for this purpose. This claim is characterized by higher lift coefficients, enhanced lift over a wider range of angles of attack, delayed stall, reduced drag coefficients and higher Lift-to-Drag ratio (L/D) of the wings/blades. This is a direct consequence of the suction of slow-moving air/water, which suppresses the adverse pressure gradients close to the surface of the wings/blades. The VoPAC Pressure Differential Device - APG suppressor can be installed and used in combination with Wind / Air / Water turbines in the following configurations: (1) Rotor Hub Variant, similar to Claim 15. (2) Off the Rotor Variant, similar to Claim 16. (3) Stand Alone Variant, similar to Claim 17. Additionally, the device can be used as an Adverse Gradient Suppressor on Oscillating Wings. The suppression of adverse pressure gradients achieved by the device, helps augment the aerodynamic characteristics of lifting and/or propulsive devices, by controlling stall and/or imposing Laminar Flow Control (LFC) on the surface of these devices.