Effects of Coupling Strategy on Performance of Overlapping Particle Technology for SPH Method

The Smoothed Particle Hydrodynamics (SPH) method has been widely applied to study complex flows with free surfaces for its capability to accurately capture large deformations. However, fully exploiting its advantages requires a sufficiently fine resolution, which can be computationally intensive. The Overlapping Particle Technique (OPT) divides the original problem domain into multiple sub-domains, allowing for variable resolutions and avoiding interactions among particles of different masses, thereby reducing computational efforts. The coupling between the sub-domains is the primary factor that affects the accuracy and stability of the solution. In this paper, a one-way OPT framework is presented for dam-break flow to investigate the inherent relationship between coupling strategy and computational performance. Two sub-domains are utilized to model the entire physical fields, in which the one with higher resolution is fully covered by the other, and an inlet-outlet boundary is added at the overlapping region to maintain the coupling. To improve computational efficiency, the position-based Verlet integration scheme is employed, and time marching is controlled by dual time-stepping criteria. Through numerical simulations based on the Weak Compressible SPH scheme, the effects of interpolation formulas, particle generation positions, and the resolution ratio between sub-domains on the solutions of 2D dam-break flow are explored and analyzed. The results demonstrate that the corrected interpolation formula outperforms the conventional formula in nearly all cases. Moreover, a smaller spacing of particle generation positions typically results in higher accuracy, while a sparsely distributed candidate position may lead to the formation of non-physical cavities near the inlet-outlet boundary. Additionally, the resolution ratio has a relatively minor impact when the corrected interpolation is adopted, whereas a large resolution ratio can reduce the error via the smoothing effect when the interpolation is based on the conventional formula. This work can provide a valuable reference for the research and application of the OPT for the SPH method.