1. Consider a Boeing 747 airliner cruising at a velocity of 550 mile/hr at a standard...

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1. Consider a Boeing 747 airliner cruising at a velocity of 550 mile/hr at a standard altitude of 38,000 ft, where the freestream pressure and temperature are 432.6 lb/ft² and 390 °R, respectively. A one-fiftieth scale model of the 747 is tested in a wind tunnel where the temperature is 430 °R. a) Calculate the required velocity and pressure of the test airstream in the wind tunnel such that the lift and drag coefficients measured for the wind-tunnel model are the same as for free flight. Assume that both viscosity and speed of sound are proportional to √T, where T is the temperature. (13 points) b) Compare the pressure obtained from part (a) with the standard atmospheric pressure, and comment on how difficult or easy it is in ground-based facility to replicate this condition. (2 points) 1. Consider a Boeing 747 airliner cruising at a velocity of 550 mile/hr at a standard altitude of 38,000 ft, where the freestream pressure and temperature are 432.6 lb/ft² and 390 °R, respectively. A one-fiftieth scale model of the 747 is tested in a wind tunnel where the temperature is 430 °R. a) Calculate the required velocity and pressure of the test airstream in the wind tunnel such that the lift and drag coefficients measured for the wind-tunnel model are the same as for free flight. Assume that both viscosity and speed of sound are proportional to √T, where T is the temperature. (13 points) b) Compare the pressure obtained from part (a) with the standard atmospheric pressure, and comment on how difficult or easy it is in ground-based facility to replicate this condition. (2 points)

Answer rating: 100% (QA)

a To calculate the required velocity and pressure of the test airstream in the wind tunnel we need to ensure that the lift and drag coefficients measured for the windtunnel model are the same as for f... View the full answer