A. numerical study of swash flows generated by bores

作者：Zhang Qinghai; Liu Philip L F^*

来源：Coastal Engineering, 2008, 55(12): 1113-1134.

DOI：10.1016/j.coastaleng.2008.04.010

• Swash zone
• Tsunami runup
• Dam-break
• Bore
• Non-linear shallow water equations
• Reynolds averaged Navier-Stokes equation
• Non-linear k-epsilon model

The dynamic processes of bore propagation over a uniform slope are studied numerically using a 2-D Reynolds Averaged Navier-Stokes (RANS) solver, coupled to a non-linear k-epsilon turbulence closure and a volume of fluid (VOF) method. The dam-break mechanism is used to generate bores in a constant depth region. Present numerical results for the ensemble-averaged flow field are compared with existing experimental data as well as theoretical and numerical results based on non-linear shallow water (NSW) equations. Reasonable agreement between the present numerical solutions and experimental data is observed. Using the numerical results, small-scale bore behaviors and flow features, such as the bore collapse process near the still-water shoreline, the 'mini-collapse' during the runup phase and the 'back-wash bore' in the down-rush phase, are described. In the case of a strong bore, the evolution of the averaged turbulence kinetic energy (TKE) over the swash zone consists of two phases: in the region near the still-water shoreline, the production and the dissipation of TKE are roughly in balance: in the region farther landwards of the still-water shoreline, the TKE decay rate is very close to that of homogeneous grid turbulence. On the other hand, in the case of a weak bore, the bore collapse generated turbulence is confined near the bottom boundary layer and the TKE decays at a much slower rate.

• 出版日期2008-12
• 单位中央民族大学