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Unformatted text preview: : ( b ) Assume the fluid is air at room temperature ( = 1.2 kg/m s), the freestream velocity is 55.0 m/s, and the characteristic area of the body is 0.510 m 2 . Calculate the drag coefficient and lift coefficient. ( c ) Suppose a 1/4 th-scale model is tested in a wind tunnel using the same air. How fast should the wind tunnel be run? Do you notice any problem with this? Explain. Any suggestions about what to do about the problem? 7 . (10 pts) A blimp is 50.0 m long and 6.25 m in diameter. As a simple approximation, we assume that the blimp is the shape of an ellipsoid , aligned with its long axis parallel to the flow direction. A propeller at the back of the blimp provides thrust. It moves through still air at 12.0 m/s. The density of the air is 1.2 kg/m 3 . Assume that the flow is turbulent . ( a ) Calculate the power required to fly the blimp through the air. ( b ) Does the blimp generate any lift? Explain....
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This note was uploaded on 07/23/2008 for the course ME 33 taught by Professor Cimbala during the Fall '05 term at Pennsylvania State University, University Park.
- Fall '05