Golfball “dimples” cause the drag drop (see Figure 12.4 and the illustration for Problem 1...

Golfball “dimples” cause the drag drop (see Figure 12.4 and the illustration for Problem 12.7) to occur at a lower Reynolds number. The table below gives the drag coefficient for a rough sphere as a function of the Reynolds number. Plot the drag for a 1.65-in.-diameter sphere as a function of velocity. Show several comparison points for a smooth sphere.

Problem 12.7

The drag coefficient for a smooth sphere is shown below. Determine the speed at the critical Reynolds number for a 42-mm-diameter sphere in air.

Figure 12.4 Drag coefficient versus Reynolds number for various objects.