基于N-S方程的高效实时烟雾模拟方法改进

发布时间：2018-01-16 11:35

本文关键词：基于N-S方程的高效实时烟雾模拟方法改进　出处：《燕山大学》2010年硕士论文　论文类型：学位论文

【摘要】：模拟各种自然现象是计算机图形学的一个重要探索领域,更是一项具有挑战性的研究课题,特别是对烟雾、云、火焰、水波等不规则物体的模拟十分困难。随着相关技术的发展,计算机模拟的烟雾被广泛应用到仿真火灾烟雾、电影特效、视频游戏、广告等各种领域,大大地提高了虚拟场景的逼真效果。本文在认真分析国内外烟雾模拟成果的基础上,针对影响烟雾模拟实时性和真实性问题,着重从以下几方面进行深入研究和探讨。首先,针对基于物理方法烟雾模拟中Navier-Stokes方程形式复杂、求解困难、影响实时性的问题,引入无量纲化方法优化Navier-Stokes方程。通过对控制烟雾运动的物理方程进行量纲分析,建立影响流体流动各因素之间的正确关系,以及从流动相似原理出发并遵循相似准则,使Navier-Stokes方程中的物理量无量纲化,把方程化为规范形式,使物理量的数值大小归一,以简化方程形式、减少计算量,并通过GPU方法加速计算,提高烟雾模拟实时性。其次,针对Navier-Stokes方程对流项和压力项求解复杂,影响烟雾模拟真实性和实时性的问题,提出用Point-Based方法求解Navier-Stokes方程对流项和压力项。利用Voronoi图离散求解区域计算压力投影,有效的缓解规则网格离散求解区域引起的数值耗散;同时,避免采用半拉格朗日方法求解Navier-Stokes方程对流项所引起的数值耗散,以便正确地捕获烟雾模拟的细节特征,在满足烟雾模拟实时性的同时提高真实性。最后,利用VC++语言、开放性图形接口OpenGL以及可编程图形硬件语言Cg在Windows平台上设计并实现烟雾模拟系统,对改进的烟雾模拟算法进行实验验证。实验结果表明:所模拟出的烟雾效果比较真实,满足了烟雾模拟真实感和实时性的要求。
[Abstract]:Simulating all kinds of natural phenomena is an important exploration field of computer graphics, and it is also a challenging research topic, especially for smoke, cloud and flame. The simulation of irregular objects such as water waves is very difficult. With the development of related technology, computer simulated smoke has been widely used in fire smoke simulation, film effects, video games, advertising and other fields. Based on the careful analysis of the results of smoke simulation at home and abroad, this paper aims at affecting the real-time and authenticity of smoke simulation. Focus on the following aspects of in-depth research and discussion. First of all, aiming at the complex form of Navier-Stokes equation in smoke simulation based on physical method, it is difficult to solve it and affects real-time performance. The dimensionless method is introduced to optimize the Navier-Stokes equation. By dimensionality analysis of the physical equation which controls the smoke movement, the correct relationship between the factors affecting the fluid flow is established. Based on the principle of flow similarity and following the similarity criterion, the physical quantity in Navier-Stokes equation is dimensionless, the equation is normalized, and the numerical value of physical quantity is normalized. In order to simplify the equation and reduce the computational complexity, the GPU method is used to accelerate the calculation to improve the real-time performance of smoke simulation. Secondly, solving the convection term and pressure term of Navier-Stokes equation is complex, which affects the authenticity and real-time of smoke simulation. The Point-Based method is used to solve the convection and pressure terms of Navier-Stokes equation, and the Voronoi diagram is used to discretize the region to calculate the pressure projection. The numerical dissipation caused by the discrete solution of the mesh is effective. At the same time, the numerical dissipation caused by the semi-Lagrangian method to solve the convection term of Navier-Stokes equation is avoided in order to capture the detailed characteristics of smoke simulation correctly. It can satisfy the real time of smoke simulation and improve the authenticity at the same time. Finally, the smoke simulation system is designed and implemented on Windows platform using VC language, open graphics interface OpenGL and programmable graphics hardware language CG. The experimental results show that the simulated smoke effect is more realistic and meets the requirements of realistic and real-time smoke simulation.
【学位授予单位】：燕山大学
【学位级别】：硕士
【学位授予年份】：2010
【分类号】：TP391.41

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