为研究波流共同作用下珊瑚礁海岸附近水动力特性,本文基于雷诺平均的 Navier-Stokes 方程(Reynolds-averaged Navier-Stokes equations,RANS)建立了2维数值波流水槽,分别采用k-ωSST湍流模型模拟湍流和流体体积法(volume of fluid,VOF)追踪自由液面.模拟定常正向流和反向流,并与只考虑波浪的情形进行对比,重点分析了水流对沿礁波高、平均水位以及破碎带附近波生流、湍动能和雷诺剪切应力的影响.结果表明,相对于纯波浪的情况,正向流使礁坪波高和增水减小,反向流使礁坪波高和增水增大,增减幅度随水流流量的增加而增大,正向流影响下破碎带附近沿水深方向整个水体均为向岸流,反向流影响下破碎带附近波谷上方为向岸流下方为离岸流,波谷下方水流强度均随着流量的增加而增大;破碎带附近的湍动能和雷诺剪切应力的随着正向流流量的增加而减小,随着反向流流量的增加而增大.
Numerical study of the hydrodynamic characteristics of reef coast under the combined effects of waves and currents
To investigate the flow characteristics around the reef coast under the combined effects of waves and currents,a two-dimensional numerical wave tank is developed based on the Reynolds-Averaged Navier-Stokes equations(RANS),the SST turbulence model is solved for the turbulence and the volume of fluid(VOF)method is used to track the free surface.Different shoreward currents and seaward currents are tested and they are compared with the wave only.The effects of current on the cross-reef wave height and mean water level as well as the mean flow field,turbulent kinetic energy,and Reynolds shear stress around the surf zone are investigated.Compared to the measurements without the current,both wave height and wave setup on the reef flat are reduced by the shoreward current but they are increased by the seaward current.Furthermore,the ranges of their variations increase with the increasing flowrate.Around the surf zone,the flows along water depth are shoreward directed in the presence of shoreward current,but they are shoreward/seaward directed above/under the wave trough in the presence of seaward current.Moreover,the magnitudes of both currents below the wave trough increase with the increasing flowrate.Finally,both the turbulence kinetic energy and the Reynolds shear stress associated the breaking waves decrease as the shoreward flowrate increases,but their values increase as the seaward flowrate increases.
万方数据
维普
