Computational Analysis of Turbulent Flow Around a Dimpled and Smooth Sphere

Steady turbulent flow around a 43-mm diameter smooth sphere and one with 245 round dimples was simulated. The turbulent flow around the sphere was attained by placing a turbulator 9 mm’s upstream of the center point. For comparison, the turbulator was also placed around the dimpled sphere. The simulation revealed stable vortical flow structure inside the dimples. A stable vortex pair in the wake region was predicted in both cases. Predicted separation point over the smooth sphere was further downstream than in the case of dimpled sphere. The predicted drag coefficient for the smooth sphere was 40% lower than that of the dimpled sphere, which was 0.35. Drag predictions are compared with previously published measurements.