Critical grid method: An extensible Smoothed Particle Hydrodynamics fluid general interpolation method for Fluid-Structure Interaction surface coupling based on preCICE

TL;DR

This work addresses the challenge of coupling meshless SPH fluids with the mesh-based preCICE framework for FSI by introducing a particle-mesh coupling (PMC) strategy that employs a critical grid as an intermediate medium on the wet interface. The authors formulate SPH fundamentals (kernel and particle approximations, momentum/continuity equations, and EOS) and then detail how preCICE's explicit/implicit schemes, data mapping, and communication can be extended to meshless solvers via PMC. A dedicated SPH adapter is implemented to realize SPH-preCICE coupling, with force interpolation from particles to the critical grid and displacement interpolation back to particles, including boundary-consistent corrections. Numerical tests on dam-break–elastic plate and dam-break–elastic sluice gate problems demonstrate the PMC method’s accuracy and stability, showing appreciable agreement with experimental benchmarks. The work enables broader adoption of meshless methods within preCICE, with open-source SPH adapter support and future plans for performance optimization and expansion to additional meshless solvers.

Abstract

Solving Fluid-Structure Interaction (FSI) problems using traditional methods is a big challenge in the field of numerical simulation. As a powerful multi-physical field coupled library, preCICE has a bright application prospect for solving FSI, which supports many open/closed source software and commercial CFD solvers to solve FSI problems in the form of a black box. However, this library currently only supports mesh-based coupling schemes. This paper proposes a critical grid (mesh) as an intermediate medium for the particle method to connect a bidirectional coupling tool named preCICE. The particle and critical mesh are used to interpolate the displacement and force so that the pure Lagrangian Smoothed Particle Hydrodynamic (SPH) method can also solve the FSI problem. This method is called the particle mesh coupling (PMC) method, which theoretically solves the mesh mismatch problem based on the particle method to connect preCICE. In addition, we conduct experiments to verify the performance of the PMC method, in which the fluid and the structure is discretized by SPH and the Finite Element Method (FEM), respectively. The results show that the PMC method given in this paper is effective for solving FSI problems. Finally, our source code for the SPH fluid adapter is open-source and available on GitHub for further developing preCICE compatibility with more meshless methods.

Figures (18)

• Figure 1: Kernel function approximation and particle approximation principle of the SPH method.
• Figure 2: preCICE is an efficient coupled library for multiphysical field simulation, which provide data mapping between non-matching grids, communication, and equation coupling schemes. Solver and preCICE are connected through their adapters (eg. Afx and Asx, $x=1,2,3,\cdots$), which call the interfaces provided by preCICE to exchange data between solids and fluids.
• Figure 3: Serial-explicit coupling scheme.
• Figure 4: Serial-implicit coupling scheme.
• Figure 5: (a) represents the mismatched mesh coupling surface of fluid and solid, (b) represents the consistent mapping principle of temperature $T$, and (c) describes the conservative mapping principle of force $F$.