Calculate the friction drag on the fiat plate when the free-stream velocity is (a) 20m/sand when it is (b) 40 m/s.

Consider compressible viscous flow over the same fiat plate as in Prob. 4.43. Assume a completely turbulent boundary layer on the plate. The free-stream properties are those at standard sea level. Calculate the friction drag on the fiat plate when  Assuming that the friction drag,  varies with velocity as , calculate the value of the exponent n based on the answers from (a) and (JJ). Prob. 4.43. The results of Example 4.4 showed that the aerodynamic force on a body is proportional to the square of the free-stream velocity. This is strictly true, however, only when the aerodynamic force is due to the pressure exerted on the surface and when the :flow is incompressible. When the aerodynamic force is also due to the distribution of frictional shear stress over the surface and/or the :flow is compressible, the “velocity squared” law does not strictly hold. The purpose of this problem is to examine how the friction drag on a body varies with free-stream velocity for an incompressible : flow. The length of each side is 4 m. Assume that the transition Reynolds number s 5 x 105 and that the free-stream properties are those at standard sea level. Calculate the friction drag on the fiat plate when the free-stream velocity is (a) 20m/sand when it is (b) 40 m/s. (c) Assuming that the friction drag, D1, varies with velocity as VO: , calculate the value of the exponent n based on the answers from (a) and (b). How close does  come to 2? That is, how close is the friction drag to obeying the velocity squared law?