The passive control on flow and heat transfer with streamwise micro grooves

Abstract

The flow behavior of smooth channel and channel with streamwise micro grooves are numerically compared at Reynolds number 3000–6000. The numerical prediction results show that the streamwise micro grooves can effectively promote the heat transport in boundary layer. In special cases, the streamwise micro grooves can suppress the ejection and sweep motions of turbulent coherent structure to a certain extent, which is conducive to the improvement of the stability of near-wall flow structure and the reduction in wall shear stress. In addition, 2.16% of drag reduction can be obtained. Furthermore, the streamwise micro grooves increase the number of large-scale vortices and destroy the thermal boundary layer. With the help of the streamwise micro grooves, Nusselt number increases by 8.2% ~ 10.7% in the range of considered Reynolds number.