A new open boundary formulation for incompressible SPH

Abstract

International audienceIn this work a new formulation for inflow/outflow boundary conditions in an incompressible Smoothed Particles Hydrodynamics (ISPH) model is proposed. It relies on the technique of unified semi-analytical boundary conditions that was first proposed for wall boundary conditions in 2013, then extended to open boundaries in the framework of weakly-compressible SPH (WCSPH). An ISPH model relying on that formulation for solid boundaries was then proposed, which is the one considered here. It includes a buoyancy model for temperature effects and a k − turbulence closure. There are two main requirements for the imposition of open boundaries in ISPH: an algorithm to let particles enter and leave the domain, and the correct imposition of open boundary conditions on the fields. Regarding the algorithm for particles creation/destruction, it relies on the variation of mass of the particles located at the open boundaries. When the mass of such a particle reaches a threshold, a new particle is released. On the other hand, the imposition of open boundary conditions on the fields is done by prescribing the value of the boundary terms appearing in the semi-analytical formulation. The formulation was first validated in 2-D on a cut dam-break, a case of propagation of a solitary wave and a Creager weir. It was then extended to 3-D and tested on a 3-D circular pipe. A preliminary application case consisting of two connected pipes at different temperatures was then simulated. The results are promising since in all cases the fluid enters and leaves the domain as prescribed and generating none or very few reflected waves

A practical approach for extracting mechanical properties of microcapsules using a hybrid numerical model

“…This is an advantage of particle-based methods which automatically resolve the conservation of mass as well as explicit capturing of the interface between different material phases. SPH has been applied to a wide range of applications such as free surface flows (Löhner et al 2006;Leroy et al 2016;Gotoh et al 2014), hydrodynamic instabilities (Rahmat et al 2014;, multi-phase flows (Rahmat et al 2016;Szewc et al 2013;Colagrossi and Landrini 2003), bluff body simulations and Fluid-Solid Interactions (Rafiee and Thiagarajan 2009;Yang et al 2014).…”

DualSPHysics: from fluid dynamics to multiphysics problems

“…Several types of open boundary approaches are available in SPH, among which the unified semianalytical model [52][53][54], the mirror particles method [55], and the buffer region strategy, originally introduced by Lastiwka et al [56], then used in many other works [57][58][59][60]. The latter approach has been chosen for implementation in DualSPHysics, mainly for its simplicity but also for its suitability to a variety of engineering applications.…”

Review of smoothed particle hydrodynamics: towards converged Lagrangian flow modelling

“…While very accurate, these approaches are quite restrictive in that mathematical derivations are kernel dependent, restricting generality of application. Nevertheless, the accuracy offered is attractive and recent works have applied the semi-analytical approach to open as well as solid boundaries in weakly compressible [62] and incompressible [63] flows. Open boundaries in coastal and offshore applications will invariably contain a free surface, and it is here that one has to return to fully numerical (rather than semi-analytical) approaches.…”