Analysis of shock wave reflection from fixed and moving boundaries using a stabilized particle method

In the present paper, the efficiency of an enhanced formulation of the stabilized corrective smoothed particle method （CSPM） for simulation of shock wave propagation and reflection from fixed and moving solid boundaries in compressible fluids is investigated. The Lagrangian nature and its accuracy for imposing the boundary conditions are the two main reasons for adoption of CSPM. The governing equations are further modified for imposition of moving solid boundary conditions. In addition to the traditional artificial viscosity, which can remove numerically induced abnormal jumps in the field values, a velocity field smoothing technique is introduced as an efficient method for stabilizing the solution. The method has been implemented for one- and two-dimensional shock wave propagation and reflection from fixed and moving boundaries and the results have been compared with other available solutions. The method has also been adopted for simulation of shock wave propagation and reflection from infinite and finite solid boundaries.

A New Stable Version of the SPH Method in Lagrangian Coordinates

The purpose of this paper is to solve some of the trouble spots of the classical SPH method by proposing an alternative approach.First,we focus on the problem of the stability for two different SPH schemes,one is based on the approach of Vila[25]and another is proposed in this article which mimics the classical 1D LaxWendroff scheme.In both approaches the classical SPH artificial viscosity term is removed preserving nevertheless the linear stability of the methods,demonstrated via the von Neumann stability analysis.Moreover,the issue of the consistency for the equations of gas dynamics is analyzed.An alternative approach is proposed that consists of using Godunov-type SPH schemes in Lagrangian coordinates.This not only provides an improvement in accuracy of the numerical solutions,but also assures that the consistency condition on the gradient of the kernel function is satisfied using an equidistant distribution of particles in Lagrangian mass coordinates.Three different Riemann solvers are implemented for the first-order Godunov type SPH schemes in Lagrangian coordinates,namely the Godunov flux based on the exact Riemann solver,the Rusanov flux and a new modified Roe flux,following the work of Munz[17].Some well-known numerical 1D shock tube test cases[22]are solved,comparing the numerical solutions of the Godunov-type SPH schemes in Lagrangian coordinates with the first-order Godunov finite volume method in Eulerian coordinates and the standard SPH scheme with Monaghan’s viscosity term.

Modelling large deformation and soil–water–structure interaction with material point method:Briefing on MPM2017 conference

The 1st International Conference on the Material Point Method for ＂Modelling Large Deformation and Soil–Water–Structure Interaction＂（MPM2017）was held in Delft,The Netherlands on 10-13 January 2017.This is the first conference organised by the Anura3D MPM Research Community,following a series of international workshops and symposia previously held in The Netherlands,UK,Spain and Italy,as part of the European Commission FP7 Marie-Curie project MPM-DREDGE.We are delighted to present seven contributions in this Special Column of the Journal of Hydrodynamics,and take this opportunity to announce that the 2nd conference,MPM2019,will be held in Cambridge,UK in January 2019.

An ISPH model for flow-like landslides and interaction with structures

An incompressible smoothed particle hydrodynamics（ISPH） model has been developed to investigate the flow-like landslide phenomena The landslide mass is idealized as rigid and perfectly-plastic material with a constant density. Unlike the widely-used explicit smoothed particle hydrodynamics（SPH） models for landslides, the Chorin＇s projection method is used herein to implicitly solve the normal stress via a pressure Poisson equation, leading to a realistic distribution of instantaneous stress fields free of spurious fluctuations. The capability of the model is demonstrated through three case studies, including the idealized granular flow, landslide interaction with a rigid barrier, and a historical cut-slope landslide in Hong Kong.