On the effects of free-stream turbulence intensity in the fluid flow and heat transfer from a sphere at subcritical Reynolds numbers

Abstract

In this work, the effect of the free-stream turbu-lence on the heat transfer and the near wake behind a sphere is studied at moderate Reynolds numbers of ¿¿ ¿ ¿¿¿¿ and ¿¿ ¿ ¿¿¿. Turbulence delays the sep-aration of the boundary layer from the sphere, while increases the drag coefficient and the heat transfer. The Nusselt number and its fluctuations in the rear zone of the sphere are increased as a consequence of a larger entrainment of turbulent flow in the recirculating zone. The length of the recirculating region and the heat transfer in the near wake is also largely affected by the free-stream turbulence.