Coupling Hair with Smoothed Particle Hydrodynamics Fluids

We present a two-way coupling technique for simulating the complex interaction between hair and fluids. In our approach, the motion of hair and fluids is simulated by evaluating the hydrodynamic forces among them based on boundary handling techniques used in SPH (Smoothed Particle Hydrodynamics) fluids. When hair makes contact with fluids, water absorption inside the hair volume can be simulated with a diffusion process by treating the hair volume as porous media with anisotropic permeability. The saturation of each hair strand is then used to derive the adhesive force between wet hair strands. This enables us to simulate the formation of hair clumps dynamically without the need to employ post clumping processes. The proposed method can be easily applied to any SPH fluid solvers as well as various hair models.