Author(s): Shun-Ichiro Hayashi; Terunori Ohmoto; Itsuro Honda; Ryu-Ichi Hirakawa
Linked Author(s): Terunori Ohmoto
Keywords: DNS; Inner secondary flow; Open-channel turbulence
Abstract: A fully-developed turbulent open-channel flow was computed to clarify the generation mechanism of inner secondary flow in a mixed-boundary corner formed by a vertical wall and a free surface using direct numerical simulation (DNS). The Reynolds number for the simulations was Reτ=150 and the aspect ratio of channel width to flow depth was 2. The maximum-velocity-dip phenomena and stable secondary currents were reasonably reproduced. The significant results were the identification of inner secondary flow which rotates toward the wall at the free surface and down away from the surface along the wall. Then, in this paper, the Reynolds momentum equations were analyzed to discuss the generation mechanism. Detailed evaluation of Reynolds stress terms and pressure terms revealed that the imbalance between them causes the inner secondary flow.
Year: 2007