Questions tagged [wind-tunnel]
A wind tunnel is a tool used in aerodynamic research to study the effects of air moving past solid objects. A wind tunnel consists of a tubular passage with the object under test mounted in the middle. Air is made to move past the object by a powerful fan system or other means.
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What weather conditions have been tested with a wind tunnel?
If I want to know how my aircraft component performs in different atmospheric conditions, I might want to test it in a wind tunnel. What sorts of weather conditions have been tested in a tunnel?
I am ...
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Aerofoil selection for a Horizontal turbine [duplicate]
I'm currently having a bit of an issue selecting the type of aerofoil I would want to use in my ridge mounted wind turbine honours project. I want to select a high lift generating aerofoil at low ...
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If an aerofoil is placed in a narrow wind tunnel, how will that affect the lift it produces?
This is NACA 0000 aerofoil:
This is just a straight line - roughly what a paper plane's aerofoil section looks like (I chose this aerofoil for its simplicity). If we put this aerofoil in a wind ...
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is it necessary for the velocity distribution profile over a flat plate to have that kind of parabolic shape?
A wind tunnel boundary layer experiment was done for a flat plate with 5 stagnation probes distributed horizontally (each probe has 5 vertical sensors) and a variable flap, for 2 different free stream ...
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Does Cd number change at different speeds during wind tunnel testing?
When meassure Cd or Cl of airplane/car in wind tunnel, does number change at different speeds, for example at 100km/h compare to 250km/h?
If yes,how much?
I know from theory that coefficents change ...
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How can I calculate the TOTAL drag of the ENTIRE airplane?
I have an aircraft similar to a Cessna 172 and am using a virtual wind tunnel software (flowdesign) to get a drag estimate. I import the airplanes 3D model and I get around 2240 lbs of drag with a ...
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What is the modern approach to extract vehicle system responses to control input? [closed]
What is the modern approach to extract vehicle system responses to control input?
Is everything thrown into a CFD simulation and the responses recorded or is something else done? Are wind tunnels ...
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How calculate lift/drag using static pressure taps in wind tunnel test?
An airfoil section in a wind tunnel has many static taps on its upper and lower surface. These static ports can only read static pressure which acts perpendicularly to the local airfoil surface.
In ...
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How can I make a serious wind tunnel?
I am looking for specifics of building and the operation of low speed wind tunnels, but most diy wind tunnels on internet are improved versions of science fair projects at best.
What would I need to ...
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How do engineers estimate the aerodynamic effects caused by jet engines or propellers in wind tunnels?
When aircraft models are tested in wind tunnels they don't seem to have engines or propellors on them. So how do engineers get correct parameters from the experiments? Do they just seal the air inlets ...
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How should I attach an aircraft model in a wind tunnel when testing wind gust/yaw stability?
Where should I attach the rod to the aircraft model when simulating wind gust /weather vane effect in wind tunnel testing? At the center of gravity, behind the CG, in front of the CG...?
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Why do wind tunnels not have oval turns?
Why do wind tunnel not have oval turns to reduce energy which is lost in sharp 90 degree turns and decrease turbulence?
Wind tunnel with oval turns:
Wind tunnel with 90 degree turns:
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Fan power for 3x3m wind tunnel? [closed]
How much power do I need for 3x3m wind tunnel,with airspeed up to 200km/h?
Some formula for calculation?
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In wind tunnel testing "same Mach number" is not "same airspeed"?
Wikipedia:
"Mach number: the ratio of the airspeed to the speed of sound should be identical for the scaled model and the actual object (having identical Mach number in a wind tunnel and around ...
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Wing vs wall to wall wing,total drag comparation at same AoA?
Compare total drag of wall to wall wing vs wing(open tips) in wind tunnel,AT SAME AoA.
My first intuition is that wall to wall wing has higher pressure drag at outward parts of wing,because side-walls ...
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Can I measure induced drag with a simple wind tunnel test?
Device can measures total drag force and lift of wing for given AoA and airflow speed.
Wing both wingtips are far away from side walls.
Airflow speed is constant all the time:50m/s
TOTAL DRAG=...
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Do wall-to-wall airfoils produce induced drag?
The walls in a wind tunnel stop air leakage around the outboard sections of an airfoil, and the pressure distribution at the center section is the same as at the outboard sections (if we neglect ...
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Wind tunnel- test section design question? [closed]
1)Why test section room is so so big,is this because to reduce interfrence between test object and walls?
2)Is test section room open to outside atmopsheric pressure or must be 100% air proof?
3)How ...
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Can a wind tunnel simulate airflow when a vehicle goes around a curve?
In real life, airflow in a turn is curved, how does a wind tunnel simulate this condition?
If we just yaw the test object at some angle in wind tunnel, do we simulate the airflow in correct way?
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What are some specific benefits of cryogenic wind tunnels?
What are some benefits to using a cryogenic wind tunnel over a more traditional one? Are there certain aerodynamic properties or principles that are better studied at low temperatures?
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is there difference b/w moving object in a fluid and static object in a moving fluid?
wind tunnel is usually based on static object in a moving fluid, but wouldn't stationary/semi wind inevitably fill the tunnel after collision, but in the real world the moving object is always meeting ...
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Which type of fan is better for wind tunnel testing?
I would like to build a small wind tunnel to test a miniaturized wing/airplane. I have two options, using axial blower (picture 1) or using centrifugal blower (picture 2). The first will be the wind ...
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Flow Straightener location
Do wind tunnels with flow straightener after the flow contractors have slower flow velocity compared to a wind tunnel with the flow straightener right after the fan? Note: I'm assuming the same fan is ...
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How to measure wind speed in a wind tunnel
I'm currently building a wind tunnel that moves air at hundreds of meters per second. How do I cheaply measure the wind speed?
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What is the explanation of this airfoil phenomenon? Why the air from below the leading edge's tip deflected up?
I have difficulties to understand this air phenomenon, why the air from below the leading edge's tip (from below the horizontal line) is deflected up and not just follow the bottom wing's surface? ...
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How to artificially increase the Reynolds number in a wind tunnel?
I'm currently scaling down a model 64 times for a wind tunnel analysis, where I'm measuring drag force (for drag coefficient) and lift force (for lift coefficient). However, I read that scaling down ...
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Pitching moment as a pure moment and its measurement with a homemade force balance
In mechanics, we learn that a force $F$ acting at a certain application point $P$ can exert a torque (also called moment of the force) about another arbitrary point $Q$ in the plane, i.e. $\tau= F \...
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Which propeller configuration is the one that generates the least turbulent flow in a wind tunnel?
I looked at the post here but still have some questions Why are push-propellers so rare, yet they are still around?
This is along the same idea but the answers are not too helpful either. Pros and ...
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Where can you find wind tunnel visualization data online?
I was wondering if there was a repository of flow visualization results somewhere online, preferably of wing sections categorised in some manner.
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Where should the support points be for testing a model wing in a wind tunnel?
When testing a certain wing profile inside a wind tunnel where should the model, small scale wing be supported? Should the support be under the center of mass of the wing or under the aerodynamic ...
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How do we derive Lift Coefficient of an airplane's wing?
In many references I read that lift coefficient ($C_l$) is a product of wind tunnel test. But many times I read the formula to calculate the coefficient of lift. From the lift equation, $$L=\frac{1}{2}...
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Why do we see a reduction in temperature in a wind tunnel by increasing the velocity, but in a real flight it's the opposite?
In a real flight, when the speed of an aircraft increases, we see an increase in temperature too. So that at high Mach numbers the surfaces of the aircraft will be very hot.
Now I have encountered ...
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Lift and Drag Coefficients using load cell data
I have a MAV and I need to find out the lift and drag coefficients for the wing and tail. I am not available with a wind tunnel so I will be using a load cell along with a separate wind source. Now I ...
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How is windspeed scaled in wind-tunnel tests?
Let's say you have a scale model that is 1:10th the size of the real thing. You want to test this in a wind-tunnel.
Do you also scale down the windspeed 10x? Why or why not? I would think it has to ...
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How is the centre of lift estimated for airplane models before they are being mounted in a wind tunnel?
They mount the airplane models or parts of an airplane like just a wing, or a rudder in wind tunnels to test their drag and lift, stability, etc.
How do they know where to hang it from or mount it on....
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Does the Reynolds number on a smaller model need to match the one of the original aircraft?
1.Airbus 380-800 :
The overall length of it , is 72.72 m and its cruise speed is 903 km/h. Based on the mean chord of wing , its Reynolds number in cruise phase is around 75 millions. Now , a 1/18 ...
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Can this design provide more lift force than thrust from engine?
The problem is depicted in the picture:
Generally, why we don't use engine blow wings to fly? Can we use wind-tunnel-like wing to generate lift force?
Can it generate more lift than thrust? If it ...
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Is there an analytical description of the NACA 642-015A profile?
While searching for symmetric profiles I stumbled across different definitions (point-clouds) of the NACA 642-015A profile.
http://airfoiltools.com/airfoil/seligdatfile?airfoil=n64015a-il
http://www....
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Does zero-lift angle of attack depend on Reynolds number?
In this post I read that, due to viscous effects, the $C_{l}$ at a given angle of attack increases slightly with the Reynolds number but it seems that it just happens near the stall angle of attack.
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How to calculate the drag on an airfoil from momentum equation (Fundamental of Aerodynamics 5th edition, J.D.Anderson)?
If you got the book, please read 2.6 section (page 135). Here is my sumary of this section:
An airfoil in a wind tunnel (wingtips were butted against both sidewalls of wind tunnel). The control ...
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What is the practical usefulness of a small home made wind tunnel?
Is a small wind tunnel, like in the video, of any value for building planes able to carry a man?
Can the lift and drag, corresponding to a scaled down wing (or segment of a wing) introduced in such a ...
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How are wind tunnels used with scale models?
This answer introduced me to the problem of using scaled models in a wind tunnel.
How are wind-tunnels used in practice (for modelling the performance of subsonic airplanes)? In particular:
Do they ...
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What was the first supersonic wind tunnel?
What was the world's first supersonic wind tunnel? Who built it and how did it work?
All I've found so far is this Wikipedia article that says:
By the end of the war, Germany had at least three ...
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What aspect ratio is best for Wind Tunnel Testing an aerofoil with Small Additives? [closed]
Vortex generators will be 3D printed on a panel, which is then to be slotted onto a foam aerofoil to be tested in the wind tunnel for performance and flow physics.
What I want to know is which aspect ...
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Are these pressure and velocity distributions calculated by CFD simulation correct?
I am simulating wind tunnel tests for a NACA64210 airfoil with the following conditions:
$P_\infty=101300$ $Pa$ ; $\rho = 1.23$ $kg/m^3$ ; $U_\infty = 29.99$ $m/s$
I performed the simulation with ...
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How should the pressure coefficient distribution from a wind tunnel experiment be interpreted?
I'm doing a wind tunnel experiment and I'm trying to plot the pressure coefficient distribution for the upper and the lower surfaces of an airfoil based on experimental data. The airfoil chord is 150 ...
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Why are wind tunnel models sometimes placed upside down?
Sometimes in wind tunnel tests, models are suspended upside-down:
Image obtained from DNW - Interference corrections
Image obtained from this Youtube video of testing at AEDC
Image obtained from ...
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What problems can be encountered if an airplane does not undergo wind tunnel testing?
SpaceShipOne did not use any wind tunnel testing. According to the Scaled Composites FAQs:
Q: Did you do wind tunnel testing?
A: No. All design refinements and performance predictions have been ...
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Why don't all wind tunnels use magnets to suspend models?
NASA and the French aerospace agency have conducted research into magnetic suspension and balancing systems (MSBS) to suspend models during wind tunnel tests, like this system in South Korea.
Where ...
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Will wind tunnel modelling ever be completely replaced by computer models? [closed]
With computer-based fluid simulation already being extremely realistic (and likely faster and cheaper than physical wind tunnels), are they, anywhere, completely replacing physical wind tunnels? If ...
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