On the effects of the free-stream turbulence on the heat transfer from a sphere

Abstract Free-stream turbulence is present in many engineering applications and known to affect both bluff body aerodynamics heat transfer. In this work, its effects on the transfer near wake behind a sphere are studied. To do this, direct large-eddy simulations of flow at moderate Reynolds numbers R e = 1000 10 4 , with levels incoming up % length scale O ( D ) being diameter, performed. At under consideration, significant changes observed. Incoming delays separation laminar boundary layer from sphere, while same time drag coefficient Nusselt number increased. The level also increases momentum surrounding fluid energises separated shear-layer. As consequence, there shrinking recirculation zone which intensifies thus, fluctuations, especially rear sphere. It shown that free-stream turbulent flux wake, larger entrainment colder surroundings, thus producing faster decay temperature intensity.