Question

2. A hovercraft weighs M =1500 kg and hovers without changing altitude. The exit flow exhausts to atmospheric pressure at sea-level. The flow is steady, incompressible and uniform properties can be assumed on all control surfaces. Assume air density = 1.22kg/m?. a) Apply and simplify the integral momentum equation in the vertical direction. Write your resulting equation here. Hints: The static pressure of the inlet flow is not at atmospheric pressure. Since the hovercraft is hovering without changing altitude, the net vertical force on the hovercraft from the air flows, pressure forces, and hovercraft weight must equal zero. b) Apply the Bernoulli equation between the inlet and a point 0 above the hovercraft where the air velocity is zero and the static pressure is atmospheric pressure. Ignore elevation changes between point 0 and the inlet. A simple equation for Pinlet, g (the gage pressure at the inlet) will result, write it here. c) Combine your equations from parts a) and b) with a simple mass conservation equation (between the inlet and exit) to find an equation for the exit velocity Vexit =f (M, g, P, Ainiet, Aexit). d) Calculate a numerical value for Vexit  Fig: 1  Fig: 2  Fig: 3  Fig: 4  Fig: 5  Fig: 6  Fig: 7