Question

The drag coefficient of a car at the design conditions of 1 atm, 25°c, and 90 km/h is to be determined experimentally in a large wind tunnel in a full-scale test. the height and width of the car are 1.25 m and 1.65 m, respectively. if the horizontal force acting on the car is measured to be 230 n, determine the total drag coefficient of this car. take the density of air at 1 atm and 25°c as ρ = 1.164 kg/m3. (round the final answer to two decimal places.)

Answer 1

Velocity = 90 km/h = 25 m/s

Drag coefficient, Cd = 2D/Density of air*Frontal area*sqr. velocity

Substituting,

Cd = (2*230)/(1.164*1.25*1.65*25^2) = 0.3066