Hood Figure 12.5 Lockheed F-104.

Q1

6. For a wing of aspect ratio AR, having an elliptical lift distribution, the induced drag coefficient is (where CL is the lift coefficient) (b) TAR CL 2TAR (d) TAR2 (a) TAR 7. Laminar flow airfoil is used to reduce the (a) pressure drag (b) induced drag (c) skin friction drag (d) wave drag 8. Set the aerofoil your chosen angle of incidence is gives a good installed pressure distribution. (a) twelve degree (b) ten degree (c) eight degree 9. The critical Mach number for a thick airfoil will be (a) lesser than a thin airfoil. (b) greater than a thin airfoil. (c) equal to a thin airfoil. (d) cannot be related to thin airfoil 10. What is the dimension for Lift coefficient? (a) N/s (b) kg/N (c) Dimensionless

Air at a pressure of 1 atm and a temperature of 250 °C is in parallel flow over a top surface of a flat plate that is maintained at a uniform temperature of 20 °C. The plate has a length of 0.35 m (in the flow direction) and a width of 0.2 m. The Reynolds number based on the plate length, ReL is 9x10“. (a) Find the rate of heat transfer to the plate. (b) If the free stream velocity of air is increased 5 times and pressure increased 4 times, what will be the rate of heat transfer? For air at 1 atm: assume k=0.0299 W/m.k, Pr =0.70. Draw sketch and show all calculations.