基于非线性压力损失边界条件的半圆型开孔潜堤水动力特性解析研究

Analytical Studies on Hydrodynamic Characteristics of Submerged Perforated Semi-Circular Breakwater Based on Non-Linear Pressure Loss Boundary Condition

基于势流理论,对半圆型开孔潜堤在波浪作用下的水动力特性进行解析研究。利用多极子展开法和分离变量法,在极坐标系下建立半圆型开孔潜堤内外流场的速度势表达式,通过迭代匹配求解开孔板处的非线性压力损失边界条件,确定速度势表示式中的展开系数,计算反射系数、透射系数、波浪力等水动力参数。将水动力参数的解析计算结果与分区边界元法的数值计算结果进行对比,符合良好。通过算例分析,明确了潜堤半径、开孔率等对反射系数,透射系数和波浪力的影响规律。研究结果可为半圆型防波堤的工程设计提供有效指导。

Based on potential theory,an analytical study on hydrodynamic characteristics of submerged perforated semi-circular breakwater is given.Multipole expansion method and separation variable method are used for establishing the velocity potential expressions in the internal and external flow fields of perforated semi-circular breakwater.The expansion coefficients in velocity potential expressions are determined by iteratively solving the non-linear pressure loss boundary condition on the perforated wall.The reflection coefficient,transmission coefficient and wave force are calculated.Calculation examples show that the convergence of the present analytical solution is rapid.The present analytical solution is also compared with the solution of multi-domain BEM,and the two solutions are in good agreement.The effects of the radius and porosity on the reflection coefficient,transmission coefficient and wave forces are thoroughly discussed.When the porosity of the breakwater increases,the reflection coefficient and the horizontal wave force acting on the breakwater decreases significantly,while the variation of the vertical force is negligible.To reach a low transmission coefficient,the optimal porosity of the breakwater is about 10%~15%at kh<2.The present research results can provide effective guidance for the engineering design of semi-circular breakwater.