Question 4 (20 points): The drag force (F,,) on a diamond-shaped body, is a function of the characteristic length (L), fluid velocity (F). density (o), and viscosity (u). (a) Write a dimensionless form of the above relation. (b) A wind tunnel test (air) on a model with a characteristic length of L4 =9 in gives the following data: Air Speed 30 38 48 56 61 ft/s 1.25 1.95 3.02 4.05 4.81 b Use these data to predict the drag force on a similar diamond-shaped body with a characteristic length of Lo =15 in placed at similar orientation in water flowing at 7.22 ft/s. Density and viscosity of air are p,. =0.00237 slug/ fi* and gy, =3.72E -7 Ibf s/ fi*, and density and viscosity of water are g =194 slug/ fi* and warder Hyer = 2.09E -5 Ibf s/ fi*, Ans: 87 Ib respectively