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ISSN Online: 2379-1748
8th Thermal and Fluids Engineering Conference (TFEC)
NUMERICAL STUDY FOR A MODE-2 ISW PROPAGATING OVER A TRAPEZOIDAL OBSTACLE WITH DIFFERENT SLOPES
Resumo
Based on the results of field observations in South China Sea, a mode-2 internal solitary wave (ISW) propagates over a variable topography (i.e., convex, and concave obstacle). The effect of different submarine obstacle on the evolution of a mode-2 ISW is the interested issue. A finite volume method based on a Cartesian grid system is adopted to solve the Navier-Stokes equations using Improved Delayed Detached Eddy Simulation model for the turbulent closure. In this study, the values of front slope are adopted from 90° (convex; positive front slope) to -90° (concave; negative front slope) to investigate the flow evolutions during a mode-2 ISW-obstacle interaction. Numerical results reveal the vortex shedding can be found before the wave propagates over a convex obstacle (i.e., slope > 0°). At the same time, the former phenomenon dissipates quickly and then is generated a liked soliton in positive cases. The waveform modification (i.e., the waveform becomes steep in lower layer and wide in upper layer) is found as the negative slope steepens. When the positive front slope, the transmitted amplitude and wave energy in very mild slope has largest decreases because of long and strong wave-obstacle interaction. Although the short and strong wave-obstacle interaction is occurred in steep positive cases, the transmitted amplitude and wave energy is larger than that in the very mild slope as the wave propagates on plateau.