Abstract: Hydraulic erosion topography is a common natural phenomenon in both real life and virtual scenes. In order to study the surface erosion by hydraulic power, a realistic simulation model is proposed by applying the smoothed particle hydrodynamics (SPH) to simulate the wetting and erosion process of the surface affected by fluid. Based on the reasonable simplified description of the real splash erosion in nature, a three stages topographic hydraulic splash erosion model is proposed. Firstly, the effect of water flow on the surface is simulated by the deformation model of projectile impacting flat target. Secondly, the calculation method of water permeability based on Darcy’s law is used to ensure the authenticity of surface water absorption and water diffusion. Finally, a new calculation model is proposed, which takes into account the influence of surface moisture on surface erosion. The experimental results show that the model can simulate the erosion effects of water flow in different directions on surface and the phenomena of surface water absorption and moisture diffusion during the erosion process.

Key words:  hydraulic erosion, smoothed particle hydrodynamics, splash erosion, Darcy’s law, wet diffusion