貫通壁チャネル乱流における究極熱伝達

抄録

By using direct numerical simulations we have investigated heat transfer in pressure-driven turbulent flows between two parallel plates on which a no-slip permeable condition is imposed for the velocity. In this boundary condition the wall-normal velocity component is supposed to be proportional to the pressure difference across the plate. In numerical simulations the Prandtl number is set to unity, and the volume-averaged streamwise velocity and temperature are kept constant by changing spatially constant steamwise pressure gradient and internal heating (or cooling) in time. By the introduction of the permeable walls we have achieved the ultimate heat transfer, in which the Stanton number is independent of the Reynolds number. This ultimate heat transfer is considered to be a consequence of the Kelvin-Helmholtz instability leading to near-wall turbulence promotion without flow separation.