Real-Time Fluid Simulation Based On Smoothed Particle Hydrodynamics

Fluid simulation is a technology that uses computers to simulate fluid physical phenomena and study fluid motion laws.Common fluids such as water flow and air flow have high research and application value in computer graphics,computational fluid dynamics,and engineering fields.With the advancement of hardware and algorithms,fluid simulation and rendering gradually meet the requirements of real-time applications,and realistic 3D real-time fluid animation becomes possible.The Smoothed Particle Hydrodynamics method is a branch of fluid simulation research based on Lagrangian particles.Compared with the traditional Eulerian grid method,it has the advantages of simple expression structure,easy handling of boundaries,and high parallelism.The main work of this thesis includes:1.Based on the Smoothed Particle Hydrodynamics method,aiming at real-time fluid simulation problems,an improved double source solver method is proposed.The position-based constant density solver is responsible for changing the particle distribution,and the velocity-based divergence free solver is responsible for correcting the particle velocity.The two solvers cooperate successively to constrain the particle position and velocity respectively to achieve fluid incompressibility.This method not only has the performance and stability of a double source term solver,but also has a lower single-step iteration time consumption and can better adapt to real-time simulation tasks.2.Based on the screen-space fluid surface reconstruction method,the procedural texture of the fluid depth and thickness is generated for the particle data,and the surface normal is calculated after smoothing the depth image using the bilateral filtering method.In order to speed up texture generation,this thesis proposes an acceleration method for adaptively sampling uniform grids,which greatly improves the speed of surface reconstruction while retaining sufficient fluid details.3.This thesis uses a physically-based real-time rendering method to sample the texture generated by the surface reconstruction process to construct a water material that is transparently mixed with the scene color.And an extended shading model including thickness-based refraction,environment map-based reflection,and noise texture-based underwater caustic effects is proposed to enhance fluid realism.This method has low computational overhead and outstanding visual effects.4.Combining the previous fluid simulation and rendering work,this thesis implements a complete particle-based real-time fluid simulation application.Additional supported features are solid and liquid collisions based on signed distance fields and potential-based gas and liquid mixing to generate foam,and provide a user interface for dynamically adjusting simulation parameters and rendering parameters.With the help of this tool,users can obtain fluid animation generated by real-time simulation and rendering according to their needs.Experiments show real-time interactive fluid animation with100 k particles at about 16 frames per second on a GTX1060 graphics card.