CN109406097A - A kind of device and method for fluid wall surface shear stress in surveying laboratory sink - Google Patents
A kind of device and method for fluid wall surface shear stress in surveying laboratory sink Download PDFInfo
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- CN109406097A CN109406097A CN201811481034.1A CN201811481034A CN109406097A CN 109406097 A CN109406097 A CN 109406097A CN 201811481034 A CN201811481034 A CN 201811481034A CN 109406097 A CN109406097 A CN 109406097A
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- G—PHYSICS
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- G01M—TESTING STATIC OR DYNAMIC BALANCE OF MACHINES OR STRUCTURES; TESTING OF STRUCTURES OR APPARATUS, NOT OTHERWISE PROVIDED FOR
- G01M10/00—Hydrodynamic testing; Arrangements in or on ship-testing tanks or water tunnels
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Abstract
The invention discloses a kind of device and methods for fluid wall surface shear stress in surveying laboratory sink, including flow cavity, pressure chamber, the first long straight glass tube and the second long straight glass tube, flow cavity is a cuboid housing, and left and right ends opening, upper surface is opened there are two first through hole；Pressure chamber is made of the first cavity body and the second cavity body, the lower surface of first cavity body is provided with the second through-hole, the lower surface of second cavity body is provided with third through-hole, second through-hole is connected with a first through hole being located at below the first cavity body, third through-hole is connected with another first through hole being located at below the second cavity body, first long straight glass tube is fixedly connected on the upper surface of the first cavity body and is connected with the first cavity body, and the second long straight glass tube is fixedly connected on the upper surface of the second cavity body and is connected with the second cavity body.The pressure difference of front and rear surfaces, is calculated the wall shear stress numerical value at the point when flowing through side wall by measuring water flow.
Description
Technical field
The invention belongs to hydraulicss and field of fluid mechanics, more particularly to one kind is for fluid walls in surveying laboratory sink
The device and method of face shear stress can be used for measuring the fluid shear stress of experimental tank bottom, side wall and periphery.
Background technique
Fluid shear stress is the important parameter in hydraulics and hydrodynamics engineering practice and theoretical research, is hindered in water flow
It is played an important role in the research for the problems such as power, riverbed and the bottom in straits wash away, sediment bypassing and pollutant are spread.It is disorderly
The when equal shearing stress of stream is considered as being made of two parts: a part is by time mean flow rate relative motion between adjacent two fluid layer
Generated viscous shearing stress, another part are the Reynolds shears as caused by fluctuating velocity:
For turbulence flow flied, fluid shear stress mainly by when equal fluid layer relative motion and the viscous shearing stress and turbulent flow that generate
The composition of Reynolds shear caused by pulsation, upper and lower level water particle mutually blend.Viscous shearing stress is due to water body different layers flow velocity
Be unevenly distributed, each layer there are caused by current difference,Eddy stress be due to turbulent fluctuation water body exchange laminar flow it
Between the shear stress that generates,In above formula, as i=j, τijFor Reynolds mormal stress, as i ≠ j, τij
For Reynolds shear；ρ is the density of water.When Reynolds number is very big, turbulent flow sufficiently development, Reynolds shear, which occupies fluid, cuts and answers
The major part of power.In the theoretical research in relation to engineer applications such as river straits, channel flow, pipeline streams and in relation to fluid,
Generally require measurement side wall fluid shear stress and its vertical distributing.And existing fluid shear stress measurement method general structure is more
Complexity is chiefly used in the measurement of fluid shear stress in minor diameter capillary.
The measurement of wall shear stress is divided into measurement indirectly and directly measurement two ways, and measurement mainly passes through measurement pair indirectly
Barometric gradient, velocity gradient, heat exchange and the other parameters that should be put, and then the relationship of these parameters and shearing stress is established, it ties
Structure is relatively simple；The directly used sensor of measurement generally all has floating unit, and cutting for being generated due to fluid viscosity is answered
Power acts on floating unit, and the displacement of floating unit and the size of shearing stress are proportional, and structure is complex, generally requires to pass through
The calibration of data is to obtain compared with accurate result.
Summary of the invention
For existing apparatus structure is complicated be not easy to application the shortcomings that, the present invention provides a kind of for surveying laboratory sink
The device and method of middle fluid wall surface shear stress solves the problems, such as that fluid wall shear stress measures in sink.
The technical proposal for solving the technical problem of the invention is as follows: one kind is for fluid walls in surveying laboratory sink
The device of face shear stress, including flow cavity, pressure chamber, the first long straight glass tube and the second long straight glass tube, the pressure
Chamber overlays the upper surface of flow cavity, and the flow cavity is a cuboid housing, and left and right ends opening, upper surface is provided with two
A first through hole；The pressure chamber is made of the first cavity body and the second cavity body, and the lower surface of first cavity body is provided with
Second through-hole, the lower surface of the second cavity body are provided with third through-hole, the second through-hole be located at below the first cavity body one the
One through-hole is connected, and third through-hole is connected with another first through hole being located at below the second cavity body, the first long straight glass
Pipe is fixedly connected on the upper surface of the first cavity body and is connected with the first cavity body, and the second long straight glass tube is fixedly connected on
The upper surface of two cavity bodies and it is connected with the second cavity body.
Further, the outer wall of the described first long straight glass tube and the second long straight glass tube is labeled with scale, scale essence
Really arrive millimeter.
Further, the flow cavity and pressure chamber are all made of transparent organic glass and are made.
It is a further object of the present invention to provide a kind of method for fluid wall surface shear stress in surveying laboratory sink,
This method realizes in above-mentioned device, this method are as follows:
Device is placed in side wall tested point, flow cavity is parallel with water (flow) direction, when water flow flows through the first cavity body and second
When the lower surface of cavity body, due to the presence of resistance, leads to the reduction of water flow pressure, pass through the first cavity body of measurement and the second cavity
The pressure difference of internal water flow, calculates the water flow shearing stress for answering observation point.
Further, this method specifically comprises the following steps:
(1) in laboratory sink test, device is placed in side wall tested point, flow cavity is parallel with water (flow) direction, and past the
Kerosene is filled in one long straight glass tube and the second long straight glass tube, until kerosene amount reaches the first long straight glass tube and the second long straight glass
1/2 to 2/3 place of glass pipe high scale；
(2) when water flow flows through the lower surface of the first cavity body and the second cavity body, due to the presence of resistance, lead to water flow
Pressure reduces, and reads the liquid level difference Δ h of the first long straight glass tube and the second long straight glass tube, is scaled pressure difference: Δ P=ρoilg
Δ h calculates corresponding wall shear stress τωNumerical value:ρoilFor the density of kerosene, g 9.8m/s2, H is
The height of flow cavity, X are the medium spacing of two first through hole, τωUnit Pa, Δ h and X unit mm, H unit m.
The present invention is lost by measurement fluid along stroke pressure using the size of indirect method measurement fluid shear stress, and then
To water flow shearing stress along the regularity of distribution in vertical line direction.There are resistances in flow process for practical viscous fluid, overcome resistance just
Part energy is consumed, is mainly reflected in the pressure loss.Pressure loss when fluid flows in straight tube is flowed by fluid
When friction caused by, referred to as along stroke pressure lose.It depend primarily on the length of pipeline, sectional dimension, medium flow velocity
With viscosity etc..In addition, the fluidised form of medium is different, it is also different along stroke pressure loss.
Must assure that in manufacturing process and be not connected between the first cavity body of pressure chamber and the second cavity body, device it is organic
Glass should not have crude or uneven phenomenon.When device leaves unused, blocked in the first cavity body using small stopper or rubber stopper
The second through-hole and the second cavity body third through-hole and two long straight glass tubes, prevent kerosene from leaking, long straight glass tube and pressure
The case where strong chamber is revealed there can be no oil droplet, in order to avoid test for contamination facility and cause measurement result inaccurate.
Beneficial effects of the present invention are as follows: can be used under laboratory environment, to fluid shear stress in indoor water tank test
Measure, the device measurement position can be changed with Binding experiment room moveable platform, measure fluid shear stress vertical line and
Latitudinal section situation.
Detailed description of the invention
Fig. 1 is device design schematic diagram；
Fig. 2 is the perspective view of apparatus of the present invention；
In figure: flow cavity 1, pressure chamber 2, the first long straight glass tube 3, the second long straight glass tube 4, first through hole 5, first are empty
Cavity 6, the second cavity body 7, the second through-hole 8, third through-hole 9.
Specific embodiment
Present invention will be described in further detail below with reference to the accompanying drawings.
For horizontal positioned rectangular section open channel flow, as shown in Figure 1, taking one section of uniform flow is measurement object, along water flow
Direction is reduced due to the presence of water flow frictional resistance along water (flow) direction pressure.The active force that water flow is subject in the horizontal direction includes:
Water flow left and right ends pressure, frictional resistance.According to the equilibrium principle of power:
P1BH=2Ff+P2BH
In formula, Ff=τωBX, then the shearing stress expression formula of available following form:
As shown in Fig. 2, a kind of device for fluid wall surface shear stress in surveying laboratory sink, including flow cavity 1,
Pressure chamber 2, the first long straight glass tube 3 and the second long straight glass tube 4, the pressure chamber 2 overlay the upper surface of flow cavity 1,
The flow cavity 1 is a cuboid housing, and left and right ends opening, upper surface is opened there are two first through hole 5；The pressure chamber
2 are made of the first cavity body 6 and the second cavity body 7, and the lower surface of first cavity body 6 is provided with the second through-hole 8, the second cavity
The lower surface of body 7 is provided with third through-hole 9, and the second through-hole 8 is connected with a first through hole 5 for being located at 6 lower section of the first cavity body,
Third through-hole 9 is connected with another first through hole 5 for being located at 7 lower section of the second cavity body, and the first long straight glass tube 3 is fixedly connected
The first cavity body 6 upper surface and be connected with the first cavity body 6, the second long straight glass tube 4 is fixedly connected on the second cavity
The upper surface of body 7 and it is connected with the second cavity body 7.
Further, the outer wall of the described first long straight glass tube 3 and the second long 4 glass tube of straight glass tube is labeled with quarter
Degree, scale are accurate to millimeter.
Further, the flow cavity 1 and pressure chamber 2 are all made of transparent organic glass and are made.
It is a further object of the present invention to provide a kind of method for fluid wall surface shear stress in surveying laboratory sink,
This method realizes in above-mentioned device, this method are as follows:
Device is placed in side wall tested point, flow cavity 1 is parallel with water (flow) direction, when water flow flows through the first cavity body 6 and
When the lower surface of two cavity bodies 7, due to the presence of resistance, lead to the reduction of water flow pressure, by measuring the first cavity body 6 and second
The pressure difference of water flow in cavity body 7 calculates the water flow shearing stress for answering observation point.
Further, this method specifically comprises the following steps:
(1) in laboratory sink test, device is placed in side wall tested point, flow cavity 1 is parallel with water (flow) direction, and past the
Light oil is filled in one long straight glass tube 3 and the second long straight glass tube 4, until lightweight oil mass reaches the first long straight glass tube 3 and the
1/2 to 2/3 place of two long 4 high scales of straight glass tube；When device normal use, if inner filling water, long straight glass tube liquid level with
The water surface is close, and transparent water body read in long straight glass tube it is unobvious, so internal be full of with light oil.Due to lightweight
The density of oil is less than the density of water, and liquid level is bigger under same pressure, so liquid level is located at the water surface or more, easily readable liquid level
Scale.In lower surface, oil will not be leaked in water body for pressure chamber aperture (the second through-hole and third through-hole) simultaneously.
(2) when water flow flows through the lower surface of the first cavity body 6 and the second cavity body 7, due to the presence of resistance, lead to water
Flowing pressure reduces, and reads the liquid level difference Δ h of the first long straight glass tube 3 and the second long straight glass tube 4, is scaled pressure difference: Δ P=
ρoilG Δ h calculates corresponding wall shear stress τωNumerical value:ρoilFor the density of light oil, g 9.8m/
s2, H is the height of flow cavity 1, and X is the medium spacing of two first through hole 5, τωUnit Pa, Δ h and X unit mm, H unit m.
The above is only a preferred embodiment of the present invention, is not intended to limit the scope of the invention, all to utilize this hair
Equivalent structure made by bright specification and accompanying drawing content or equivalent process conversion, and it is relevant to be directly or indirectly used in other
Technical field is included within scope of patent protection of the invention.
Claims (5)
1. a kind of device for fluid wall surface shear stress in surveying laboratory sink, which is characterized in that including flow cavity, pressure
Strong chamber, the first long straight glass tube and second long straight glass tube etc., the pressure chamber overlays the upper surface of flow cavity, the stream
Dynamic chamber is a cuboid housing, left and right ends opening, and upper surface opens that there are two first through hole；The pressure chamber is by the first sky
Cavity and the second cavity body composition, the lower surface of first cavity body are provided with the second through-hole, and the lower surface of the second cavity body is opened
Have a third through-hole, the second through-hole is connected with a first through hole being located at below the first cavity body, third through-hole be located at the
Another first through hole below two cavity bodies is connected, and the first long straight glass tube is fixedly connected on the upper surface of the first cavity body
And be connected with the first cavity body, the second long straight glass tube be fixedly connected on the upper surface of the second cavity body and with the second cavity body
It is connected.
2. a kind of device for fluid wall surface shear stress in surveying laboratory sink according to claim 1, special
Sign is that the outer wall of the first long straight glass tube and the second long straight glass tube is labeled with scale, and scale is accurate to millimeter.
3. a kind of device for fluid wall surface shear stress in surveying laboratory sink according to claim 1, special
Sign is that the flow cavity and pressure chamber are all made of transparent organic glass and are made.
4. a kind of method for fluid wall surface shear stress in surveying laboratory sink, which is characterized in that this method is in right
It is required that being realized in the described in any item devices of 1-3, this method are as follows:
Device is placed in side wall tested point, flow cavity is parallel with water (flow) direction, when water flow flows through the first cavity body and the second cavity
When the lower surface of body, due to the presence of resistance, lead to the reduction of water flow pressure, by the first cavity body of measurement and the second cavity body
The pressure difference of water flow calculates the water flow shearing stress for answering observation point.
5. according to the method described in claim 4, it is characterized in that, this method specifically comprises the following steps:
(1) in laboratory sink test, device is placed in side wall tested point, flow cavity is parallel with water (flow) direction, long toward first
Light oil is filled in straight glass tube and the second long straight glass tube, until kerosene amount reaches the first long straight glass tube and the second long straight glass
1/2 to 2/3 place of pipe high scale；
(2) when water flow flows through the lower surface of the first cavity body and the second cavity body, due to the presence of resistance, lead to water flow pressure
It reduces, reads the liquid level difference Δ h of the first long straight glass tube and the second long straight glass tube, be scaled pressure difference: Δ P=ρoilG Δ h,
Calculate corresponding wall shear stress τωNumerical value:ρoilFor the density of light oil, g takes 9.8m/s2, H is stream
The height of dynamic chamber, X are the medium spacing of two first through hole, τωUnit Pa, Δ h and X unit mm, H unit m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811481034.1A CN109406097A (en) | 2018-12-05 | 2018-12-05 | A kind of device and method for fluid wall surface shear stress in surveying laboratory sink |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201811481034.1A CN109406097A (en) | 2018-12-05 | 2018-12-05 | A kind of device and method for fluid wall surface shear stress in surveying laboratory sink |
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| CN109406097A true CN109406097A (en) | 2019-03-01 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115406625A (en) * | 2022-10-28 | 2022-11-29 | 顶星科技南京有限公司 | Simulation wave motion test device |
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| CN107247156A (en) * | 2017-07-31 | 2017-10-13 | 长江大学 | A kind of flow rate measuring device and implementation based on pressure sensitive |
| CN108387483A (en) * | 2018-01-23 | 2018-08-10 | 大连理工大学 | A kind of wall shear stress measurement method |
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2018
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Patent Citations (5)
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|---|---|---|---|---|
| WO2004001344A1 (en) * | 2002-06-21 | 2003-12-31 | Bühler AG | Method for determining rheological parameters of a fluid |
| CN1793810A (en) * | 2005-12-23 | 2006-06-28 | 清华大学 | Flat plate wall fluid friction resistance mensuring device based on open circulation |
| CN201015071Y (en) * | 2006-12-15 | 2008-01-30 | 刘卫 | Device for demonstrating the relation of liquid pressure intensity and flow velocity |
| CN107247156A (en) * | 2017-07-31 | 2017-10-13 | 长江大学 | A kind of flow rate measuring device and implementation based on pressure sensitive |
| CN108387483A (en) * | 2018-01-23 | 2018-08-10 | 大连理工大学 | A kind of wall shear stress measurement method |
Non-Patent Citations (1)
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| CN115406625A (en) * | 2022-10-28 | 2022-11-29 | 顶星科技南京有限公司 | Simulation wave motion test device |
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Application publication date: 20190301 |
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