水砂混相流运动的CIP-DEM耦合数值模型

为建立精确模拟水砂混合流(如:挟砂溃坝溢流)问题的数值计算方法,提出了模拟固液混相流运动的垂向二维CIPDEM法耦合数值计算模型。模型采用CIP(constrained interpolation profile scheme)法求解描述水体运动的Navier-Stokes流体运动方程,采用DEM(discrete element method)法求解描述泥沙粒子团运动的牛顿力学方程;并通过水砂间的相互作用关系将水-砂运动进行耦合。通过分别对溃坝溢流和砂体下落的单相体运动进行数值模拟并与前人的实验结果进行对比,验证了CIP法流体计算模型和DEM法砂体计算模型妥当。在此基础上,采用所建立的CIP-DEM水砂耦合数值计算模型对干床面上的挟砂溃坝溢流问题进行了数值模拟,计算得出的挟砂溃坝溢流中的水、砂运动形态和运动过程与Zhang(2009)等的实验结果吻合良好,表明提出的CIP-DEM耦合模型在对具有大自由表面变形的水砂运动问题的模拟中具有较好的适用性。

A Vertical 2-Dimentional CIP-DEM Coupling Numerical Model for Water-Sand Two Phase Flows

: In this study,a CIP-DEM coupling numerical model for the simulation of water-sand two phase flows has been developed. In the numerical model, the CIP (Constrained Interpolation Profile Scheme) and DEM(Discrete Element Method)methods are adopted respectively to solve Navier-Stokes equation for fluid motions and to solve Newton mechanics equations for sediment movement, the CIP and DEM model are coupled together by considering sand and water interaction. The CIP fluid calculation model and DEM sand body calculation model were validated through application to the simulation of dam-break current and sand body collapse process respectively, and the numerical results fit well with the experimental data. Moreover, the CIP-DEM coupling model was used to the calculation of dam break induced water-sand flow. Comparison with the experimental results indicates that the proposed CIP-DEM model can well represent the process of water-sediment movement in dam-break flow. It can thus conclude that the proposed CIP-DEM coupling model is an appropriate candidate method for simulating solid-liquid two phase flow with large free surface deformation.