wind tunnel

• Pictured: Engineers making a check on body of a model of a supersonic aircraft before a test run in the 10ft x 10ft Supersonic Wind Tunnel test section. 31 July 1957

Wind tunnel – For more than a century, wind tunnels have proven instrumental tools in the examination of aerospace, architectural, vehicular, sports and other engineering systems.

wind tunnel research

• pressure-sensitive paint. Here’s how it works: Molecules in the paint fluoresce under ultraviolet (UV) light. They absorb some of the light’s energy and re-emit it as visible light. As a result, the paint seems to glow. How brightly depends on the pressure from the wind. The more pressure, the less the paint glows under UV light. Images of the wind tunnel test show where those pressure points are.Green laser light makes tiny particles in the air show up so engineers can see how air or other fluids will flow around this model of the Orion command capsule during a wind tunnel test at NASA’s Ames Research Center at Moffett Field, Calif.

Meet the people in wind tunnel research Engineering

• Nettie Roozeboom aerospace engineer with NASA’s Ames Research Center at Moffett Field, Calif. A wind tunnel lets researchers see how fast-moving air affects scale models of different things. “It’s not just for airplanes and space vehicles,” Roozeboom says. Model cars, models of cities, and even tennis, soccer and other balls go inside wind tunnels. There they get blasted with air.

That’s a drag

Simulating a Wind Tunnel in the Garage (video 3:06) – Shawn uses a wind tunnel app and help from a ski coach to analyze his ski aerodynamics. He then designs a low-drag helmet. Watch to see how big a difference it makes to the drag coefficient.

• Ask – How aerodynamic is he in the original configuration? What changes can be made to to improve his flow?
• Imagine – How can the software simulation help improve the flow? How is this like using a wind tunnel?
• Plan, Create – With some easy changes – removing heavy bulky clothing, changing stance, how much improvement was achieved?
• Improve – By making additional modifications to the helmet, they were able to future improve the flow (reduce the coefficient of drag).

That’s engineering

• air pressure – The force exerted by the weight of air molecules.
• buffeting – Irregular force exerted on an object, such as that which turbulence exerts on an airplane.
• drag coefficient – a dimensionless quantity that is used to quantify the drag or resistance of an object in a fluid environment such as air or water. It is used in the drag equation, where a lower drag coefficient indicates the object will have less aerodynamic or hydrodynamic drag. The drag coefficient is always associated with a particular surface area.
• |fluorescent – Capable of absorbing and reemitting light. That reemitted light is known as a fluorescence.

Engineering ideas

• inlet and diffuser testing, gust generation, boundary layers, shapes, aerodynamic profile, fluid, draw wall, smoke probe, visualization, pressure field, velocity field, wind speed, coefficient of drag

Do it
Now it is your turn. Here are some challenges for you to work on…

• Wind Tunnel (interactive simulation, app, lite – free) – Draw obstacles and watch the fluid flow around. Experiment with different sizes, shapes, aerodynamic profiles. Interact with the fluid, draw walls, insert smoke probe, use eraser tool. Visualization modes: particles, smoke, pressure field, velocity field. Wind tunnel (with adjustable wind speed), free mode (with no constrained wind).
• download and use Autodesk ForceEffect Flow design and evaluate a shape. Modify your design and re-evaluate the flow simulation.

Learn more…

• Autodesk ForceEffect Flow – 2D flow simulation software. Create freehand concept designs or use object detection technology to capture geometry from your environment, and then simulate the aerodynamic performance of your design. Modify your geometry to explore design options and experiment with different visualization modes for optimal results viewing. Available for iOS, Android, Chrome
• NASA – Drag Coefficient – a number that aerodynamicists use to model all of the complex dependencies of shape, inclination, and flow conditions on aircraft drag.