Meshfree modeling of a fluid-particle two-phase flow with an improved SPH method
Meshfree modeling of a fluid-particle two-phase flow with an improved SPH method
复制标题
使用改进的 SPH 方法对流体-颗粒两相流进行无网格建模
DOI：
10.1002/nme.5935
复制
发表时间：
2018
影响因子：
2.9
通讯作者：
Liu M. B.
中科院分区：
文献类型：
--
作者：
Zhang Z. L.;Walayat K.;Chang J. Z.;Liu M. B.
由于流体-颗粒界面复杂且不断运动，流体-颗粒两相流非常复杂，数值模拟也极具挑战性。无网格法和粒子法的最新发展为移动边界的流体流动建模提供了替代方案。本文提出了一种改进的光滑粒子流体动力学（SPH）方法来模拟牛顿流体中的粒子沉降（二维）。改进的SPH包括一个增强的粒子近似方案，一个有效的固体边界处理算法，人工应力模型，和湍流模型。通过在有限粒子方法中解耦场变量及其导数，提出了一种解耦有限粒子方法，该方法在SPH模拟中平衡了精度、效率和稳定性，而不需要求解冗余和具有挑战性的校正矩阵方程。提出了一种耦合的动态固体边界处理方法，以提高固定和移动固体边界附近的计算精度。在SPH运动方程中加入人工应力项，消除了可能出现的拉伸失稳现象。大涡模拟模型被纳入SPH描述湍流效应在高雷诺数。利用改进的SPH沿着结合有限元虚拟边界法进行了四种不同的颗粒沉降试验。结果表明，改进的SPH方法可以获得比传统SPH方法更好的结果，同时与有限元虚拟边界法和其他来源的结果进行了良好的比较。
Fluid‐particle two‐phase flows are very complex and quite challenging to numerically simulate due to the complex and constantly moving fluid‐particle interface. Recent developments in meshfree and particle methods provide alternatives in modeling fluid flows with moving boundaries. In this paper, a modified smoothed particle hydrodynamics (SPH) method is developed to simulate particle sedimentation (two‐dimensional) in Newtonian fluids. The modified SPH includes an enhanced particle approximation scheme, an effective solid boundary treatment algorithm, the artificial stress model, and a turbulence model. By decoupling a field variable and its derivatives in a finite particle method, a decoupled finite particle method is presented, which balances accuracy, efficiency, and stability in SPH simulations without the necessity of solving redundant and challenging corrective matrix equations. A coupled dynamic solid boundary treatment is developed to improve the accuracy near the fixed and moving solid boundaries. The artificial stress term is added into the SPH equations of motion to remove the possible tensile instability phenomenon. The large eddy simulation model is incorporated into the SPH to describe the turbulence effects at high Reynolds numbers. Four different particle sedimentation tests are conducted using the modified SPH along with the finite element fictitious boundary method. It is demonstrated that the improved SPH method can achieve much better results than the conventional SPH while showing a good comparison with the results from the finite element fictitious boundary method and from other sources.