Question

Answer All Questions and show work

1. (10pts) What is the speed of sound in air at T=-50C? Show work. Ans: 299m/s

2. (10pts) A plane is travelling at 1000km/hr at T=-50C. What is the Mach number M? Ans: M=0.93

3. (20pts) What is the adiabatic/Total temperature (TT) of an SR71 flying at Mach 3.5 if the static temperature is T=-50C? Ans: 769K

4. (10pts) What is the speed of sound in Neon gas at T=25C? Ans: 453m/s. Your FE reference will have useful information in the Thermodynamics section.

5. (20pts) A torpedo is tested in a wind tunnel in air at T=25C. It is intended to be used in water at T=10C. The model of the torpedo is 1/5th scale (all dimensions are 1/5th of the real thing on the test model to be tested in air). The intended velocity of the real torpedo in the water is V=30m/s. What is the velocity of air in the wind tunnel for the 1/5th scale torpedo? Ans: 179m/s.

6. The Prandtl number is . Where Cp is the specific heat at constant pressure, ? is the viscosity, and k is the thermal conductivity (not 1.4).What is the Prandtl number for air at T=25C? Ans: 0.715. SHOW WORK

Answer 1

Question 1. Speed of sound in air at T=50 degree celcius

= 330 + 0.61 x T

= 330 + 0.61 x (-50)

= 299.5 m/sec

Question 2. Mach Number = Local velocity / spped of sound

plane velocity 1000 km/hr = 277.7 m/sec

mach number = 277.7/299.5= 0.93

Question 3.

kindly if you have more than one question ask them separately