Flow past a transversely rotating sphere at Reynolds numbers above the laminar regime

Abstract

The flow past a transversely rotating sphere at Reynolds numbers of Re=500-1000 is directly simulated using an unstructured finite volume collocated code. The effect of rotation rate on the flow is studied by increasing the dimensionless rotation rate, Ω∗, from 0 to 1.20, where Ω∗ is the maximum sphere surface velocity normalised by the free stream velocity. This study investigates the marked unsteadiness of the flow structures at Re=500-1000. Comparison with previous numerical data (Giacobello et al., J. Fluid Mech., vol. 621, 2009, pp. 103-130; Kim, J. Mech. Sci. Technol., vol. 23, 2009, pp. 578-589) reveals a new flow regime, namely a 'shear layer-stable foci' regime, besides the widely r..