Development of a real-time fluid simulator for an interactive virtual environment: Improvement of density feedback in SPH

In this research, we developed a real-time fluid simulator for a haptic interface to display a virtual environment including 3-dimensional fluid by using smoothed particles hydrodynamics (SPH). SPH is a type of particle method and is suitable for a fast computation; however, it is difficult to incorporate sufficient fluid incompressibility in SPH for simulating a real-time process. This is because SPH was originally developed to study compressible fluid dynamics. In this paper, we propose a new control method using nonlinear feedback to compensate for elements that interfere with incompressible motions and propose its implementation method that does not significantly increase the computation time. Finally, simulations are performed to compare the proposed method with a conventional method, and the effectiveness of the proposed method is quantitatively demonstrated from the standpoints of computation time and incompressibility.