A coupled SPH-FDM method for simulations of unsteady flows

Abstract

The fluid-flexible-structure interaction (FFSI) is characterized by the large deformation, the thin structure, and the complex of the flow field. Accurately simulating FFSI poses three challenges, which are the reproduction of thin structure, the capture of moving interface, and the numerical stability of multi-physics field coupling, respectively. In this study, the FFSI is simulated by the smoothed particle hydrodynamics (SPH) because of its natural advantage in dealing with the moving interface. The shell model with single-layer particles[1] is introduced into SPH to simulate the thin flexible structure. The truncation error caused by the single-layer boundary is modified by the normal flux approach[2]. κ-ε turbulence model is introduced into SPH to enhance the numerical stability and capture complex flow details. In addition, other techniques or models that ensure the efficiency and stability of the calculation are used in this study, including PST (particle shifting technique), δ-SPH method, and GPU (graphics processing unit). The flows around the single filament are simulated to verify the accuracy and stability of the current FFSI algorithm based on the SPH method.

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