In some wind tunnels, the test-section wall is porous or perforated; fluid is sucked out to provide a thin viscous boundary layer. the wall of the test section is 4 m long and contains 800 holes of 6-mm diameter per square meter of area. the suction velocity out each hole is vs = 10 m/s, and the test section entrance velocity is v1 = 45 m/s. assuming incompressible flow of air at 20c and 1 atm, compute (a) v0, (b) the total wall suction volume flow, (c) v2, and (d) vf.