Simulate Typical Natural Phenomenon Based On Fluid Model

The simulation of realistic natural phenomena has been a hotspot and one of the most difficult tasks in Computer Graphics. It has been widely applied in many domains such as special effects of movie,3D computer animations, computer games and virtual reality. With the improvement of computer performance and the development of GPU-accelerated technology, increasingly high demand appears for the simulation of realistic natural phenomena. Traditional simulations of complex natural phenomena were commonly dealt through the particle system, but Particle system is too simple and didn't consider the physical principles behind these natural phenomena. Smoke, rain, waves, most common natural phenomenon have very complex physical principles. For volcanic eruptions, landslides and other disaster phenomenon, the laws of physics are even more complex. Physical based natural phenomena simulations are more realistic, but the drawback is the calculation is large. So it is difficult to achieve real-time, we have to get a balance between realism and real-time. The simulations here attend to achieve a certain degree of realism with real-time rendering. The main research based on fluid models of natural phenomena, which included two popular computational fluid methods SPH and LBM, is the main direction of this thesis.. And we selected seawater, volcanic eruptions, smoke to do experimental photorealistic rendering.Chapter One in this thesis outlines the significance of the study and research of natural phenomena and reviewed the related methods used to simulation seawater, volcanic eruptions, smoke. And we pointed out the direction of our research which is to simulation natural phenomena based on fluid model.Chapter Ⅱ of this paper first introduces the hydrodynamic equations, Navier-Stokes equations, and then introduces two classic models of the hydrodynamics SPH and LBM.The third chapter of this paper consider the advantages of the SPH method and the FFT method, combinate the two method to simultate the seawater, and two important algorithm Near-Particle search algorithm, Marching Cubes algorithm. Chapter Ⅳ is the scene for a volcanic eruption. We proposed LBM fluid model to use in the simulation of the diffusion of volcanic eruptions with magma. We first introduced the characteristics of a volcanic eruption, and then describes the basic principle of the Free surface based on LBM to achieve the results, then analyzed and summarized it。A combination of methods based on the LBM fluid model and particle systems are discussed in Chapter ⅡⅤ.We use the LBM to calculate the speed of the particle where the spatial grid points. Then according to the specific location of the particles in the space lattice, the three linear interpolations are used to calculate the precise particle physics speed. And then simulate the dynamic effects of the spread of smoke. At the same time, we used CUDA to accelerate the rendering efficiency.Finally, we made a summary and outlook and pointed out the trends of future research.