波浪对双层圆弧型贯底式开孔介质防波堤的绕射

Wave diffraction from a double-layered arc-shaped bottom-mounted porous breakwater

为研究波浪对双层圆弧型贯底式开孔介质防波堤的绕射问题,利用比例边界有限元方法(SBFEM)建立该问题的半解析解模型.分析时将双层圆弧延伸构建出2个虚拟同心圆可将整个流场可划分成2个有限域和1个无限域.利用变分原理推导出了关于势函数的各个子域SBFEM方程,并对SBFEM方程进行了求解.数值算例验证了该方法是一种只需离散最外边界而且用很少单元便能得到精确结果的高效算法.给出了短峰波波向、相对波数、内外半径比、圆弧段的位置、张角以及孔隙影响系数等因素对整个结构波浪绕射的影响.结果表明,双层圆弧型贯底式开孔介质防波堤与以上参数的变化密切相关.

To solve the problem of wave diffraction from a double-layered arc-shaped bottom-mounted porous breakwater,a semi-analytical model was established by the scaled boundary finite element method（SBFEM）.The double-layered porous arcs were extended to form two imaginary complete circular cylindrical interfaces.As a result,the entire computational domain was divided into three sub-domains,which included two bounded and one unbounded sub-domains.A variational principle formulation was used to derive the SBFEM equations in each sub-domain,and then the SBFEM equation of each sub-domain was solved.The numerical results show that the present method yields excellent results with quite a few discrete nodes on the outmost virtual circle along with a quick convergence rate.The influences of varying short-crested wave direction,the relative wave number,the location,field angle,annular spacing,and the porosities of the arcs on the entire structure as well as the diffracted wave contour were extensively examined.Results show that the sheltering effects on the arc-shaped porous breakwater are closely related to those parameters.