Some students want to visualize flow over a spinning baseball. Their fluids laboratory has a nice water tunnel into which they can inject multicolored dye streaklines, so they decide to test a spinning baseball in the water tunnel (Fig. P7–45E). Similarity requires that they match both the Rey n olds number and the Strouhal number between their model test and the actual baseball that moves through the air at 85 mi/h and spins at 320 rpm. Both the air and the water are at 68°F. At what speed should they run the water in the water tunnel, and at what rpm should they spin their baseball?

FIGURE P7–45E

Transcribed Image Text:

V P, μ Water tunnel test section Spinning baseball Dye injection Shield n Strut - Motor