We develop and fully characterize a meshfree Lagrangian (particle) model for continuum-based numerical modeling of dry and submerged granular flows. The multiphase system of the granular material and the ambient fluid is treated as a multi-density multi-viscosity system in which the viscous behaviour of the granular phase is predicted using a regularized viscoplastic rheological model with a pressure-dependent yield criterion. The numerical technique is based on the Weakly-Compressible Moving Particle Semi-implicit (WC-MPS) method. The required algorithms for approximation of the effective viscosity, effective pressure, and shear stress divergence are introduced. The capability of the model in dealing with the viscoplasticity is validated for the viscoplastic Poiseuille flow between parallel plates. The model is then applied and fully characterized (with respect to the various rheological and numerical parameters) for dry and submerged granular collapses with different aspect ratios. The numerical results are evaluated in comparison with the available experimental measurement in literature as well as some complementary experimental measurements, performed in this study. The results show the capabilities of the presented model and its potential to deal with a broad range of dry and submerged granular flows. It also revealed the impotent role of the regularization, effective pressure, and shear stress divergence calculation methods on the accuracy of the results.

中文翻译：

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基于连续介质的干燥和淹没颗粒流建模的多相无网格粒子方法

我们开发并充分表征了无网格拉格朗日（粒子）模型，用于基于连续介质的干燥和水下颗粒流数值建模。颗粒材料和周围流体的多相系统被视为多密度多粘度系统，其中颗粒相的粘性行为使用具有压力相关屈服准则的正则化粘塑性流变模型进行预测。数值技术基于弱可压缩移动粒子半隐式 (WC-MPS) 方法。介绍了近似有效粘度、有效压力和剪切应力发散所需的算法。对于平行板之间的粘塑性泊肃叶流，模型处理粘塑性的能力得到验证。然后应用该模型并充分表征（相对于各种流变学和数值参数）具有不同纵横比的干燥和水下颗粒坍塌。将数值结果与文献中可用的实验测量以及本研究中进行的一些补充实验测量进行比较。结果显示了所提出模型的能力及其处理各种干燥和水下颗粒流的潜力。它还揭示了正则化、有效压力和剪应力发散计算方法对结果准确性的影响。将数值结果与文献中可用的实验测量以及本研究中进行的一些补充实验测量进行比较。结果显示了所提出模型的能力及其处理各种干燥和水下颗粒流的潜力。它还揭示了正则化、有效压力和剪应力发散计算方法对结果准确性的影响。将数值结果与文献中可用的实验测量以及本研究中进行的一些补充实验测量进行比较。结果显示了所提出模型的能力及其处理各种干燥和水下颗粒流的潜力。它还揭示了正则化、有效压力和剪应力发散计算方法对结果准确性的影响。