Numerical Investigation of the Flow Around a Golf Ball at Around the Critical Reynolds Number and its Comparison with a Smooth Sphere

The flow over a stationary golf ball has been numerically investigated by conducting large-eddy simulations in the subcritical, critical and supercritical regimes. A direct comparison of features of flow fields was made to a smooth sphere model. Particular attention was paid to the effect that the golf ball dimples have on the development of lateral force and wake structures. In the subcritical regime, the lateral force varies irregularly in time for both the golf ball and the smooth sphere, and the wake structures of these two models appear to be similar, indicating the limited effect of the surface roughness on the flow behaviors in this regime. In the critical regime, both the golf ball and the smooth sphere exhibit a larger magnitude lateral force oscillation compared to the subcritical cases, while the wavelengths of the flow structures show differences between the golf ball and the smooth sphere. In the supercritical regime, both the golf ball and the smooth sphere are subjected to a nonzero lateral force during a long time interval. However, the magnitude of the lateral force acting on the golf ball is much smaller due to the relatively more concentrated and less asymmetric wake structures compared to the smooth sphere.