The flow structures of a transversely rotating sphere at high rotation rates

Abstract

This paper studies the flow structures surrounding a transversely rotating sphere for the previously unreported conditions of flow Reynolds numbers of Re = 100-300 and a rotation rate in the range Ω* = 1:25-3:00, where Reynolds number is based on sphere diameter and the free stream velocity and rotation rate Ω* is defined as the maximum sphere surface velocity normalised by free stream velocity. The flow remains steady at Re = 100. At Re = 250 and 300, the flow can be classified into 2 flow regimes at these rotation rates. Flow at lower rotation rates is dominated by the well known Kelvin-Helmholtz type instability vortex formation mechanism which produces regular, coherent vortices. As rota..