Author(s): Hai Zhu; Lingling Wang; Hongwu Tang
Linked Author(s): Hongwu Tang, Lingling Wang
Keywords: Large-eddy simulation; Internal solitary waves; Vortex shedding; Boundary layer
Abstract: A dynamic coherent eddy model (DCEM) of large-eddy simulation (LES) is employed in the present study to model the complex interaction of internal solitary waves (ISW) and background current. The ISW is generated in a stable stratified two-layer water system in a three dimensional numerical internal wave tank. The LES model is validated by both theoretical solution of KdV equation and experimental data. The results show that background current can trigger vortex shedding at the upstream foot of the ISW in the bottom boundary layer, draining energy continually from the ISW. The vortex shedding frequency is about 0. 2Hz and the coherent vortices propagating to the downstream can enhance the transition of flows from laminar to turbulent. The energetic coherent vortices disturb the ISW-induced flow field, deform the pycnocline and can even disintegrate the ISW. Such ISW-Current interaction has great impact on water environment and sediment vertical transport in the benthic boundary layer.
Year: 2013