Graphics processing unit-accelerated smoothed particle hydrodynamics—Finite difference method and the application for the flow around a cylinder with forced motions

The finite difference method (FDM) is a widely used grid-based method with high computational accuracy and efficiency. Smoothed particle hydrodynamics (SPH) is a meshless particle method, which can easily deal with the fluid flow with the free surface and moving boundary conditions. Considering the different advantages of the two methods, a hybrid approach is developed by coupling FDM with SPH. To improve the computational efficiency, compute unified device architecture is used to develop a graphics processing unit parallel computing model for the SPH-FDM coupling method. At low Reynolds number, some flow cases (static, rotation, and oscillation) of a cylinder are simulated. The particle shifting technology is used to maintain the uniform distribution of the particles when the cylindrical boundary moves. The results obtained by the coupling method are in good agreement with reference results, which indicates the acceptable accuracy and stability of the coupling method. Then, the flow past a translating cylinder with a constant velocity is simulated, and the influence of the translating velocity on the flow field is discussed. The results indicate that the translational velocity can accelerate the flow separation near the boundary layer of the object, speed up the vortex shedding process, and enhance the forces acting on the object. Therefore, the translating velocity can be used as an effective flow control method.