UNIFIED ENGINEERING Fall 2005

Ian A. Waitz

Problem T10 (Unified Thermodynamics)

An aircraft is traveling against a headwind. Assume R = 287 J/kg-K, c_p = 1003.5 J/kg-K, c_v = 716.5 J/kg-K, g = 1.4. (LO# 4)

a) If the temperature of the atmosphere is 260K and the wind is moving at 10 m/s relative to the ground, what temperature would a thermometer read if it is fixed to the ground?

b) What temperature would a weather balloon read if it was carried along with the wind?

c) For a thermometer mounted on an airplane that is flying into the wind at 300 m/s relative to the moving air mass, what temperature is read?

d) If the thermometer were mounted on the leading edge of a fan blade in the front of the engine, and at the location of the thermometer the blade speed (orthogonal to the aircraft flight direction) was 250 m/s relative to the airplane, what temperature would be read by the thermometer?