台阶式地形上双垂板透空系统的水动力学特性

Hydrodynamic performance of two vertical plates penetrating system mounted over stepped bottom

基于开源计算流体动力学软件OpenFOAM中的工具箱waves2Foam,通过在双垂板透空系统下方布置不同尺寸的台阶式地形(潜堤),对规则波-双垂板-地形耦合系统的水动力学特性进行数值分析.在不同入射波况作用下,研究双垂板的间距和台阶式地形的尺寸对结构系统前/后的反/透射系数、波能的黏性耗散率及双垂板间的液面相对振动幅值等水动力参数的影响.此外,探究波浪非线性对相关水动力参数的影响.结果表明:合理布置台阶式地形尺寸,如令地形的长度与波长的比值约为1.0,能够有效减小双垂板系统的波能反射和透射,并可获得适中的黏性耗散率;地形的存在会加剧双垂板间的液面振动幅度,有效提升两板间的波能捕获能力;波高的增大会造成反射和透射系数的减小,增大黏性耗散率,降低板间液面振动幅值.

The hydrodynamic performance of regular wave-two vertical plates-topography coupled system,comprised by two vertical penetrating plates mounted over a stepped bottom(submerged breakwater)with different dimensions,were analyzed by the use of the toolbox waves 2 Foam based on the open source software OpenFOAM.The effects of the gap between the two plates and the dimension of the stepped bottom on the hydrodynamic characteristics,such as reflection and transmission coefficients,viscous dissipation ratio of wave energy,and relative oscillating amplitude of the free surface between the two plates,were examined systematically under the action of different incident waves.In addition,the nonlinear effect of wave on the hydrodynamic parameters was investigated.Results showed that a proper dimension of the stepped bottom,for example that the ratio of topography length to wavelength was approximately equal to 1.0,was beneficial for reducing the reflection and transmission coefficients and obtaining a satisfactory viscous dissipation ratio.The presence of the stepped bottom enhances the oscillating amplitude of the free surface between the two plates and effectively improves the capacity of capturing wave energy.Furthermore,the increase of wave height leads to the reduction of the reflection and transmission coefficients,the enhancement of the viscous dissipation ratio,and the drop of the oscillating amplitude of the free surface between the two plates.