Flow Separation and Vortex Dynamics in Waves Propagating over A Submerged Quartercircular Breakwater

The interactions of cnoidal waves with a submerged quartercircular breakwater are investigated by a ReynoldsAveraged Navier–Stokes(RANS) flow solver with a Volume of Fluid(VOF) surface capturing scheme(RANSVOF) model. The vertical variation of the instantaneous velocity indicates that flow separation occurs at the boundary layer near the breakwater. The temporal evolution of the velocity and vorticity fields demonstrates vortex generation and shedding around the submerged quartercircular breakwater due to the flow separation. An empirical relationship between the vortex intensity and a few hydrodynamic parameters is proposed based on parametric analysis. In addition, the instantaneous and time-averaged vorticity fields reveal a pair of vortices of opposite signs at the breakwater which are expected to have significant effect on sediment entrainment, suspension, and transportation,therefore, scour on the leeside of the breakwater.

基于参数分析法的GNSS测波浮标波浪方向谱估计

随着全球导航卫星系统的不断进步,基于GNSS实时精密单点定位技术的波浪测量受到广泛关注。将GNSS技术结合浮标观测应用于波浪谱观测与估计,需要海洋方向谱估计基础作技术支持。首先,以频谱分析理论为基础,对频谱估计进行验证。再基于参数分析法,建立了方向谱数据处理程序;以波浪骑士测得浮标位移数据为案例,对比了分析结果与波浪骑士处理结果,两者基本一致;针对参数分析法的方向函数估计中易出现函数为负的情况,给出了修正方法。