A two-dimensional Segmented Boundary Algorithm for complex moving solid boundaries in Smoothed Particle Hydrodynamics

A Segmented Boundary Algorithm (SBA) is proposed to deal with complex boundaries and moving bodies in Smoothed Particle Hydrodynamics (SPH). Boundaries are formed in this algorithm with chains of lines obtained from the decomposition of two-dimensional objects, based on simple line geometry. Various two-dimensional, viscous fluid flow cases have been studied here using a truly incompressible SPH method with the aim of assessing the capabilities of the SBA. Firstly, the flow over a stationary circular cylinder in a plane channel was analyzed at steady and unsteady regimes, for a single value of blockage ratio. Subsequently, the flow produced by a moving circular cylinder with a prescribed acceleration inside a plane channel was investigated as well. Next, the simulation of the flow generated by the impulsive start of a flat plate, again inside a plane channel, has been carried out. This was followed by the study of confined sedimentation of an elliptic body subjected to gravity, for various density ratios. The set of test cases was completed with the simulation of periodic flow around a sunflower-shaped object. Extensive comparisons of the results obtained here with published data have demonstrated the accuracy and effectiveness of the proposed algorithms, namely in cases involving complex geometries and moving bodies.