Flow characteristics for a 31-ft-diameter prototype parachute are to be determined by tests of a 2.0-ft-diameter model parachute in a water tunnel. Some data collected with the model parachute indicate a drag Fm = 20 lb when the water velocity is 4 ft/s. A) Find the predictor equation. Assume the drag to be a function of the velocity, V, the fluid density, rho, and the parachute diameter, D. Note that model variables have subscripts m.
F = (p / pm)(V / Vm)2 (D /Dm)2 Fm
B) Use the model data to predict the drag on the prototype parachute falling through air at 11 ft/s. F = 28.53 lb