On the treatment of solid boundary in smoothed particle hydrodynamics

As a popular meshfree particle method, the smoothed particle hydrodynamics (SPH) has suffered from not being able to directly implement the solid boundary conditions. This influences the SPH approximation accuracy and hinders its further development and application to engineering and scientific problems. In this paper, a coupled dynamic solid boundary treatment (SBT) algorithm has been proposed, after investigating the features of existing SPH SBT algorithms. The novelty of the coupled dynamic SBT algorithm includes a new repulsive force between approaching fluid and solid particles, and a new numerical approximation scheme for estimating field functions of virtual solid particles. The new SBT algorithm has been examined with three numerical examples including a typical dam-break flow, a dam-break flow with a sharp-edged obstacle, and a water entry problem. It is demonstrated that SPH with this coupled dynamic boundary algorithm can lead to accurate results with smooth pressure field, and that the new SBT algorithm is also suitable for complex and even moving solid boundaries.</div

DPD simulation of multiphase flow at small scales

Small scale multiphase fluid motion is fundamentally important for applications in environmental, biological and chemical engineering as well as many other areas. Due to the existence of complex geometries, arbitrarily moving interfaces, and large density and viscosity contrast, simulation of small scale multiphase flows has been a formidable task for traditional grid-based numerical methods. This paper presents the application of a meso-scale, Lagrangian particle method, dissipative particle dynamics (DPD), for simulating multiphase fluid flows. For multiple component multiphase flows, with properly selected coefficients, the conventional DPD model can be directly used. For single component multiphase flows, the conservative weight function describing DPD particle-particle interactions has to be modified to model the existing liquid-gas phases. The effectiveness of the DPD model in simulating multiphase flows has been demonstrated by two numerical examples of twocomponent two phase flow, and one-component two phase flow. ©2010 IEEE