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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1answer
63 views

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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427 views

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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Can you fly a plane in a wind tunnel?

There are very large wind tunnels out there. Wouldn't it be very efficient to test new airplanes flying them "on the spot" inside of these tunnels? That is, in free flight - not mounted to a pylon? ...