The following wind tunnel test data from a 1:16 scale model of a bus are available:

Using the properties of standard air, calculate and plot the dimensionless aerodynamic drag coefficient,

versus Reynolds number Re=ρVw μ, where w is model width. Find the minimum test speed above which C_D remains constant.
Estimate the aerodynamic drag force and power requirement for the prototype vehicle at 100 km hr. (The width and frontal area of the prototype are 8 ft and 84 ft², respectively.)

Transcribed Image Text:

Air speed (m/s) Drag force (N) 18.0 21.8 26.0 30.1 35.0 38.5 40.9 44.1 46.7 3.10 4.41 6.09 7.97 10.7 12.9 14.7 16.9 18.9