波浪与抛石潜堤相互作用的MPS法数值模型研究

Numerical Study of Wave Interaction with Permeable Structures by Using MPS Seepage Flow Model

为了研究波浪与抛石潜堤相互作用过程中大自由表面变形和堤内渗流等强非线性紊流运动问题,利用改进的MPS法,建立了模拟波浪与抛石潜堤相互作用的MPS法数值计算模型。模型将抛石潜堤假定为均质多孔介质,采用Drew的二相流运动方程描述多孔介质内外的流体运动;通过在动量方程中增加非线性阻力项,并引入亚粒子尺度紊流模型,模拟波浪与可渗结构物相互作用过程中的紊流运动。选取“U”型管中多孔介质内渗流过程和孤立波与可渗潜堤相互作用两个典型的渗流问题,通过将数值计算结果与理论解和实测值的对比分析,对所提出的MPS法紊流渗流模型的模拟精度进行验证。结果表明:基于改进的MPS法构建的垂向二维紊流渗流模型可以很好地再现“U”型管中多孔介质内渗流以及波浪作用下可渗潜堤内外的复杂流场,显著缓解流-固界面处的压力震荡与粒子分布不均匀问题,实现了较高的模拟精度。

In order to study the intensive nonlinear turbulent flow motions such as large free surface deformation and seepage flow within breakwaters occurring in the wave interaction with permeable structures such as rubble-mound breakwaters,a numerical model is established for simulating the wave interaction with permeable structures by using an improved moving particle semi-implicit method(MPS).In this MPS model,the permeable structure is assumed to be a homogeneous porous media and the fluid motions inside and outside the media are described by using the two-phase flow motion equation proposed by Drew.The turbulent flow motion in the wave interaction with permeable structures is simulated by adding a nonlinear resistance item into the momentum equation and by using the sub-particle-scale(SPS)turbulence model as well.To verify the simulation accuracy of the MPS seepage flow model,the seepage flow motion inside the porous media within a U-shaped pipe and the solitary wave propagation over a submerged rubble-mound breakwater are selected and the numerical calculations,the theoretical solutions and the measured values are compared.By using the vertical two-dimension seepage flow model established based on the MPS method,both the seepage flow motion inside the porous media within the U-shaped pipe and the complex flow fields inside and outside the permeable breakwater under the wave action can be reproduced well.Moreover,problems such as pressure vibration and inhomogeneous particle distribution occurring at the fluid-solid boundary can also be relieved significantly,thus realizing high simulation accuracy.