In Lagrangian particle‐based methods such as smoothed particle hydrodynamics (SPH), computing totally divergence‐free velocity field in a flow domain with the smallest error possible is the most critical issue, which might be achieved through solving pressure Poisson equation implicitly with higher particle resolutions. However, implicit solutions are computationally expensive and may be particularly challenging in the solution of multiphase flows with highly nonlinear deformations as well as fluid‐structure interaction problems. Augmented Lagrangian SPH (ALSPH) method is a new alternative algorithm as a prevalent pressure solver where the divergence‐free velocity field is achieved by iterative calculation of velocity and pressure fields. This study investigates the performance of the ALSPH technique by solving a challenging flow problem such as two‐dimensional flow around a cylinder within the Reynolds number range of 50 to 500 in terms of improved robustness, accuracy, and computational efficiency. The same flow conditions are also simulated using the conventional weakly compressible SPH (WCSPH) method. The results of ALSPH and WCSPH solutions are not only compared in terms of numerical validation/verification studies, but also rigorous investigations are performed for all related physical flow characteristics, namely, hydrodynamic coefficients, frequency domain analyses, and velocity divergence fields.

中文翻译：

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计算有效的不可压缩流增强拉格朗日SPH的开发及其与WCSPH模拟通过圆柱流的定量比较

在基于拉格朗日粒子的方法（例如平滑粒子流体动力学（SPH））中，计算流域中的完全无散度的速度场是可能的最小误差，这是最关键的问题，这可以通过对较高粒子隐式求解压力泊松方程来实现决议。但是，隐式解决方案的计算量很大，在具有高度非线性变形以及流固耦合问题的多相流解决方案中可能尤其具有挑战性。增强拉格朗日SPH（ALSPH）方法是一种流行的压力求解器，它是一种新的替代算法，其中通过对速度和压力场进行迭代计算来实现无散度的速度场。本研究通过解决具有挑战性的流动问题（例如绕雷诺数范围为50到500的圆柱周围的二维流动）来研究ALSPH技术的性能，以提高鲁棒性，准确性和计算效率。使用常规的弱可压缩SPH（WCSPH）方法也可以模拟相同的流动条件。不仅在数值验证方面比较了ALSPH和WCSPH解决方案的结果/验证研究，但还要对所有相关的物理流动特征进行严格的研究，即流体动力系数，频域分析和速度散度场。