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How a wind tunnel measures forces and moments on a test airplane?
In some wind tunnel tests, the aerodynamic forces and moments on the model are measured directly. The model is mounted in the tunnel on a special machine called a force balance. The output from the balance is a signal that is related to the forces and moments on the model.
What is the purpose of wind tunnel test?
Researchers use wind tunnels to learn more about how an aircraft will fly. NASA uses wind tunnels to test scale models of aircraft and spacecraft. Some wind tunnels are big enough to hold full-size versions of vehicles. The wind tunnel moves air around an object, making it seem like the object is really flying.
How does a wind tunnel increase the speed?
We want the highest possible velocity in the test section of the wind tunnel. For a supersonic wind tunnel, we contract the flow until it chokes in the throat of a nozzle. We then diffuse the flow which increases the speed supersonically. The test section of the supersonic tunnel is placed at the end of the diffuser.
Where is the test section of a supersonic wind tunnel?
For a supersonic wind tunnel, we contract the flow until it chokes in the throat of a nozzle. We then diffuse the flow which increases the speed supersonically. The test section of the supersonic tunnel is placed at the end of the diffuser.
When does the flow choke in a wind tunnel?
When the velocity reaches the speed of sound (M = 1), the flow chokes and the Mach number can not be increased beyond M = 1. We want the highest possible velocity in the test section of the wind tunnel. For a supersonic wind tunnel, we contract the flow until it chokes in the throat of a nozzle.
How are wind tunnels used to test aircraft?
Aerodynamicists use wind tunnels to test models of proposed aircraft. In the tunnel, the engineer can carefully control the flow conditions which affect forces on the aircraft. By making careful measurements of the forces on the model, the engineer can predict the forces on the full scale aircraft.