CN111255777A - Method suitable for controlling dynamic skin flow of object - Google Patents
Method suitable for controlling dynamic skin flow of object Download PDFInfo
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- CN111255777A CN111255777A CN202010092760.5A CN202010092760A CN111255777A CN 111255777 A CN111255777 A CN 111255777A CN 202010092760 A CN202010092760 A CN 202010092760A CN 111255777 A CN111255777 A CN 111255777A
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- flow
- texture
- flow separation
- vortex generator
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- 238000000034 method Methods 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 claims abstract description 54
- 238000000926 separation method Methods 0.000 claims abstract description 30
- 230000000694 effects Effects 0.000 claims abstract description 5
- 229920000728 polyester Polymers 0.000 claims description 14
- 239000004033 plastic Substances 0.000 claims description 10
- 239000002985 plastic film Substances 0.000 claims description 4
- 229920006255 plastic film Polymers 0.000 claims description 4
- 238000003698 laser cutting Methods 0.000 claims description 2
- 239000007788 liquid Substances 0.000 claims description 2
- 238000011217 control strategy Methods 0.000 abstract description 8
- 238000006243 chemical reaction Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 230000008859 change Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 230000007246 mechanism Effects 0.000 description 2
- 238000002156 mixing Methods 0.000 description 2
- UJCHIZDEQZMODR-BYPYZUCNSA-N (2r)-2-acetamido-3-sulfanylpropanamide Chemical compound CC(=O)N[C@@H](CS)C(N)=O UJCHIZDEQZMODR-BYPYZUCNSA-N 0.000 description 1
- 241001669680 Dormitator maculatus Species 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000006056 electrooxidation reaction Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 239000003292 glue Substances 0.000 description 1
- 230000010355 oscillation Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
- F15D—FLUID DYNAMICS, i.e. METHODS OR MEANS FOR INFLUENCING THE FLOW OF GASES OR LIQUIDS
- F15D1/00—Influencing flow of fluids
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
Abstract
The invention relates to a method for controlling dynamic skin flow of an object, which attaches a material with a deformable structure to the surface of the object, the material and the object can move relatively, the material is stretched and shrunk by utilizing the mechanical instability of the material, and the conversion of a flat surface and a 3D texture surface of the material is carried out, in particular to the following steps: when there is flow separation on the surface of the object, the material is stretched to produce a textured surface with a vortex generator effect, which inhibits flow separation, and when there is no flow separation on the surface of the object, the material is contracted to return the surface of the object to a smooth state, preventing the generation of additional resistance. Compared with the prior art, the method adopts a passive flow control strategy, has strong adaptability and can be used for flow devices such as cylindrical turbulence devices, wings and the like; the dynamic flow control strategy is used, the expansibility is good, and the flow separation control under various variable working conditions can be realized through stretching in different degrees; and a mature passive control strategy is adopted, so that the cost is low and the reliability is high.
Description
Technical Field
The invention relates to a flow separation control method, in particular to a method suitable for dynamic skin flow control of an object.
Background
The flow separation can cause the aircraft resistance to be rapidly increased, and the flow state is complex, so that the aerodynamic force is nonlinearly changed, and the maneuverability and the stability of the aircraft are influenced. It is of great engineering importance to take flow control measures to inhibit the development of the separation flow. Flow control techniques include active flow control techniques and passive flow control techniques.
Active flow control (e.g., synthetic jet, electromagnetic control, etc.) is a new area of research created by the intersection of control science and hydrodynamics, primarily applied to shear flows, including free shear layers and boundary layers. In shear flow, vorticity is generated by the object plane, and active control of flow comes from control of vorticity.
The synthetic jet is a micro flow control device, and the interaction of the synthetic jet and the incoming flow of the outer flow field can change the current flow line state to generate the change of the wall surface shape, so that the flow state is influenced by the length scale which is one to two orders higher than the characteristic length scale of the synthetic jet. At present, the control mechanism of the synthetic jet driven by piston oscillation is still unclear, while the control mechanism of other synthetic jet devices is generally considered to be the spanwise instability of a series of vortex pairs and the interaction thereof. However, due to the inherently non-linear nature of synthetic jets, angle, velocity and frequency are coupled to one another, and therefore, choosing optimal control parameters is often difficult and time consuming.
The research of the flow active control under the action of the electromagnetic force has the advantages of realizability, particularly the research of the closed-loop control can be regarded as an important bridge for realizing the theory and the application of the separation active control, but the electromagnetic force control has the problems of low efficiency, electrochemical corrosion and the like besides the complexity of a common model of the separation active control and the difficulty in analysis.
Active separation active control faces complex problems, flow phenomena are often quite complex, a Navier-Stokes (NS) equation which is a basic control equation of hydrodynamics is a strong nonlinear partial differential equation, and practical problems are often not solved except some simplest boundary conditions at present.
The passive control is flow control without auxiliary energy consumption, and the conventional passive flow control strategies such as a vortex generator and the like mainly adopt a method of changing a physical model of an object, such as adding a flap on the object, and the vortex generator is a method commonly used in the passive flow control, can delay flow separation, but cannot effectively inhibit the flow separation in an off-design state, and even can cause extra resistance. Therefore, it is an effective measure to adopt a new dynamic flow control strategy.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provide a method which has strong adaptability, low cost and high reliability and is suitable for controlling the dynamic skin flow of an object.
The purpose of the invention can be realized by the following technical scheme:
a method for controlling dynamic skin flow of an object, which comprises the steps of attaching a deformable material to the surface of the object, wherein the material and the object can move relatively, and stretching and shrinking the material by utilizing the mechanical instability of the material to convert a flat surface of the material into a 3D texture surface, specifically: when there is flow separation on the surface of the object, the material is stretched to produce a textured surface with a vortex generator effect, which inhibits flow separation, and when there is no flow separation on the surface of the object, the material is contracted to return the surface of the object to a smooth state, preventing the generation of additional resistance.
Preferably, the material is a polyester plastic thin layer, and has certain strength and flexibility.
The polyester plastic thin layer is in a long strip shape, two ends of the polyester plastic thin layer are connected with a tough material similar to DuPont paper through high-viscosity liquid similar to glue, the tough material is connected with an object through a hinge, and stretching of dynamic skin is achieved through rotation of the hinge
The material is obtained by designing a programming pattern and adopting modes such as laser cutting, and the programming pattern has ductility and mechanical instability.
The position of the 3D texture is the position of the object corresponding to the vortex generator with the best control effect.
And the height of the 3D texture is the height of a boundary layer corresponding to the object under the corresponding flowing working condition.
The angle of the 3D texture in the incoming flow direction is the same as the optimal mounting angle of the vortex generator corresponding to the object
The 3D texture is composed of multiple rows of same patterns, corresponds to different wing profiles, and is determined by experiments to have different row numbers.
The length-to-height ratio of the 3D texture is the same as the length-to-height ratio of the object corresponding to the optimal vortex generator.
Compared with the prior art, the invention has the following advantages:
1. a passive flow control strategy is adopted, so that the adaptability is strong, and the device can be used for flow devices such as cylindrical turbulence, wings and the like;
2. the dynamic flow control strategy is adopted, the expansibility is good, and the flow separation control under various variable working condition conditions can be realized through stretching in different degrees;
3. and a mature passive control strategy is adopted, so that the cost is low and the reliability is high.
Drawings
FIG. 1 is a schematic structural diagram of a deformable material according to the present embodiment;
FIG. 2 is a schematic diagram of a programming pattern for designing the material of the present embodiment;
FIG. 3 is a 3D texture map of the material of this embodiment after stretching;
reference numerals:
1 is a programming pattern; and 2 is a 3D texture.
Detailed Description
The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.
Examples
A method for dynamic flow separation control that attaches a structurally deformable material to a surface of an object and allows relative movement of the material and the object. By utilizing the mechanical instability of the material and stretching and shrinking the material, the conversion between a flat surface and a 3D texture surface of the material can be realized. When the surface of an object has flow separation, the material is stretched to generate a texture surface similar to a vortex generator, so that the blending of the boundary layer and the external flow is improved, and the flow separation is inhibited. When there is no flow separation, the material is allowed to contract and the surface of the object returns to a smooth state, preventing the generation of additional resistance, the flow control method comprising the steps of:
1. when the flow separation needs to be controlled, stretching the polyester plastic thin layer and the DuPont paper material connected with the polyester plastic thin layer to a certain height, and converting the programmed pattern into a 3D texture for opening;
2. when the flow separation is not required to be controlled, the stretched polyester plastic film and the connected DuPont paper material are attached to an object on the flat surface.
The deformable material is cut with a certain texture, one end is fixed at a certain position of the object, and the other end can be stretched and moved.
The programming pattern has good ductility and mechanical instability.
The polyester plastic thin layer is a highly deformable thin layer material and can be well attached to the surface of an object in an unstretched state.
The DuPont paper material has strong toughness and tensile property, and can be well attached to the folded corner of an object.
The position of the 3D texture after stretching is the position with the best control effect of the vortex generator corresponding to the corresponding object, the height of the 3D texture after stretching is the height of the corresponding boundary layer of the object under a certain condition, the angle of the 3D texture in the direction of incoming flow is the same as the mounting angle of the optimal vortex generator corresponding to the object, and the length-height ratio of the 3D texture after stretching is the same as the length-height ratio of the optimal vortex generator corresponding to the object.
As shown in fig. 1, it is a schematic structural diagram of a deformable material in this embodiment to complete dynamic flow separation control. The following synchronization control steps will be described in detail with reference to fig. 2, taking this material as an example for an airfoil NACA 0018:
1. when the flow separation needs to be controlled, stretching the polyester plastic thin layer and the DuPont paper material connected with the polyester plastic thin layer to a certain height, and converting the programmed pattern into a 3D texture for opening;
2. when the flow separation is not required to be controlled, the stretched polyester plastic film and the connected DuPont paper material are attached to an object on the flat surface.
In step 1, a flow separation device is attached to the surface of an object;
in step 2, the object is in a flow field, stretching the thin polyester plastic layer and the dupont paper material connected thereto to a height that converts the programmed pattern into a 3D texture opening.
The 3D texture is composed of multiple rows of the same patterns, corresponds to different wing profiles, and is determined by experiments to be different in row number.
The invention attaches the structure deformable material on the surface of the object and can realize relative movement with the object. The structure deformable material is cut by certain texture, one end of the structure deformable material is fixed at a certain position of an object, and the other end of the structure deformable material can be stretched and moved.
The invention adopts passive flow control, realizes the formation of a texture surface similar to a vortex generator by stretching a structural deformable material, improves the mixing of an interface layer and the external flow, and inhibits flow separation.
Claims (8)
1. A method for controlling the dynamic skin flow of an object is characterized in that a material with a deformable structure is attached to the surface of the object, the material and the object can move relatively, the material is stretched and shrunk by utilizing the mechanical instability of the material, and the flat surface and the 3D texture surface of the material are converted, specifically: when there is flow separation on the surface of the object, the material is stretched to produce a textured surface with a vortex generator effect, which inhibits flow separation, and when there is no flow separation on the surface of the object, the material is contracted to return the surface of the object to a smooth state, preventing the generation of additional resistance.
2. The method of claim 1, wherein the material is a thin layer of polyester plastic.
3. The method of claim 2, wherein the polyester plastic film is in the form of an elongated strip, and both ends of the polyester plastic film are connected to the flexible material through the high viscosity liquid, the flexible material is connected to the object through a hinge, and the dynamic skin stretching is achieved through the rotation of the hinge.
4. The method of claim 1, wherein the material is configured to be stretchable and mechanically unstable by designing a programming pattern using laser cutting.
5. The method according to claim 1, wherein the center of the 3D texture is a position of the object where the corresponding vortex generator is best controlled.
6. The method according to claim 1, wherein the height of the 3D texture is the height of the boundary layer corresponding to the object under the corresponding flow condition.
7. The method of claim 1, wherein the 3D texture is comprised of multiple rows of the same pattern.
8. The method of claim 1, wherein the 3D texture length to height ratio is the same as the length to height ratio of the object corresponding to the optimal vortex generator.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010092760.5A CN111255777B (en) | 2020-02-14 | 2020-02-14 | Method suitable for controlling dynamic skin flow of object |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010092760.5A CN111255777B (en) | 2020-02-14 | 2020-02-14 | Method suitable for controlling dynamic skin flow of object |
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| Publication Number | Publication Date |
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| CN111255777A true CN111255777A (en) | 2020-06-09 |
| CN111255777B CN111255777B (en) | 2021-06-08 |
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| CN202010092760.5A Expired - Fee Related CN111255777B (en) | 2020-02-14 | 2020-02-14 | Method suitable for controlling dynamic skin flow of object |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008094177A (en) * | 2006-10-10 | 2008-04-24 | Japan Aerospace Exploration Agency | Vortex generator |
| JP2010203409A (en) * | 2009-03-05 | 2010-09-16 | Mitsubishi Heavy Ind Ltd | Blade body for fluid machine |
| CN102358416A (en) * | 2011-09-05 | 2012-02-22 | 西安交通大学 | Aerodynamic high-performance aerofoil for aircraft |
| CN102530242A (en) * | 2011-12-01 | 2012-07-04 | 中国航天空气动力技术研究院 | Wingtip noise control and device |
| JP2013057390A (en) * | 2011-09-09 | 2013-03-28 | Yamaguchi Univ | Vortex generator for flow on wall surface |
| CN109436293A (en) * | 2018-11-21 | 2019-03-08 | 南京航空航天大学 | A kind of shock wave control device |
| CN110015407A (en) * | 2017-12-21 | 2019-07-16 | 空中客车德国运营有限责任公司 | The flowing ontology with compressible Skin System of the vehicles |
-
2020
- 2020-02-14 CN CN202010092760.5A patent/CN111255777B/en not_active Expired - Fee Related
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008094177A (en) * | 2006-10-10 | 2008-04-24 | Japan Aerospace Exploration Agency | Vortex generator |
| JP2010203409A (en) * | 2009-03-05 | 2010-09-16 | Mitsubishi Heavy Ind Ltd | Blade body for fluid machine |
| CN102358416A (en) * | 2011-09-05 | 2012-02-22 | 西安交通大学 | Aerodynamic high-performance aerofoil for aircraft |
| JP2013057390A (en) * | 2011-09-09 | 2013-03-28 | Yamaguchi Univ | Vortex generator for flow on wall surface |
| CN102530242A (en) * | 2011-12-01 | 2012-07-04 | 中国航天空气动力技术研究院 | Wingtip noise control and device |
| CN110015407A (en) * | 2017-12-21 | 2019-07-16 | 空中客车德国运营有限责任公司 | The flowing ontology with compressible Skin System of the vehicles |
| CN109436293A (en) * | 2018-11-21 | 2019-03-08 | 南京航空航天大学 | A kind of shock wave control device |
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| CN111255777B (en) | 2021-06-08 |
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Granted publication date: 20210608 |