A fluid–structure interaction model for free-surface flows and flexible structures using smoothed particle hydrodynamics on a GPU

This paper presents the development of a numerical model for violent hydrodynamics of free-surface flows interacting with flexible structures using the meshless smoothed particle hydrodynamics (SPH) method accelerated with a graphics processing unit (GPU). The present work implements a unified SPH framework to solve both the fluid and structural dynamics within the open-source SPH code DualSPHysics. Well-known deficiencies with SPH-based structural modelling (linear inconsistency, tensile instability and rank deficiency) are addressed by adopting a Total Lagrangian formulation with kernel correction and zero-energy mode suppression. The fluid–structure coupling is handled via manipulation of the existing boundary condition within DualSPHysics, which does not require any geometrical knowledge of the interface. This, together with the unified SPH framework, permits straightforward implementation within DualSPHysics and retains its parallel scalability on hardware acceleration platforms, in particular on GPUs. An extensive validation and profiling of the proposed model is carried out for a range of challenging 2-D and 3-D test cases incorporating violent free-surface flows, nonlinear structural dynamics and complex fluid–structure interactions, and its performance is characterised and quantified. The analysis shows good agreement between the proposed model and analytical/benchmark solutions from the literature. Furthermore, the GPU profiling shows speedups on a single GPU of up to 40, compared to an optimised 12-core (24 threads) central processing unit (CPU) version. These findings indicate the proposed model is a viable and efficient approach to simulating violent free-surface fluid–structure interactions.