2. Consider a low-speed Open-Return subsonic wind tunnel with an inlet-to-throat area ratio of 10. The tunnel is turned on, and the pressure difference between the inlet (the settling chamber) and the test section is read as a height difference of 12cm on a U-tube mercury manometer. (a) Calculate the velocity of the air in the test section. The density of liquid mercury can be taken to be 1.21 x 104 kg/m. (8 marks) (b) Calculate the Reynolds and Mach number for a wing section placed into the tunnel. (5 marks) Assume that a Pitot tube is inserted into the test-section flow of the wind tunnel. The tunnel test section is completely sealed from the outside ambient pressure. (c) Calculate the pressure measured by the Pitot tube, assuming the static pressure at the tunnel inlet is atmospheric at: (i) Sea level (ii) 5000ft. Page 3 (6 marks) (6 marks)