| Summary: | 碩士 === 國立成功大學 === 水利及海洋工程學系碩博士班 === 101 === In this study, a two-dimensional Reynolds Averaged Navier-Stokes equations and the turbulence model are developed to simulate the viscous flow field near seawalls. The complex free surface configuration is captured using the Particle Level Set Method. The Improved Immersed Boundary Method (IIBM) is applied to represent the fluid-solid interaction in the vicinity of irregular solid boundary under the Cartesian grid system. To validate the accuracy of numerical model, the results were compared with the experimental data, including the deformation of wave on a steep sloping bed (Tsai et al., 1997), the water surface elevation on a mild sloping bed (Ting et al., 1994), and the wave pressure on the vertical seawall (Sundar et al., 2010). The numerical model is applied to investigate the viscous flow fields induced by periodic waves propagating on three different seawalls, involving vertical wall and steep seawalls with slope of 1:2 and 1:5. The free-surface evolutions, the wave pressure on the seawalls, the bottom shear stress prior to seawalls and the time-averaged flow field are discussed. The results reveal that the reverse flow within the boundary layer is related to the instantaneous wave elevations. An accompanying steady recirculating cells were observed in the time-averaged flow field of standing wave. However, breaking wave leads to an undertow on the seawall surface.
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