抄録
The direct numerical simulation (DNSs) with a spectral method are performed to study the effects of spanwise rotation on a turbulent Poiseuille flow at very low-Reynolds numbers. At the small rotation and Reynolds numbers, the region of the zero absolute vorticity, typically observed in the mean velocity profile of a rotating Poiseuille flow, disappears in the channel center, and the mean velocity gradient becomes opposite to that of zero absolute vorticity. When it disappears, very long low-speed streaks coiled by twisted vortical structures, dominate the flow, where low-speed fluids near a wall are excessively pumped up, and trapped into the channel center by the larger-scale twisted vortices away from the wall.
