面向多相流场景的流体交互现象模拟

Fluid simulation for complex scenarios involves a variety of media and the interactions between them, which leads to the difficulties for the fluid realistic simulation. Therefore, 3D modeling method for fluid interactive phenomena is studied in this project which orienting the multi-phase flow scenarios. This project intends to solve the problems of multi-phase fluids modeling, gas - liquid coupling modeling, fluid-rigid interaction and boundary handling, which aims to create realistic effects of multi-phase flow and fluid interactive phenomena. The main contents of this project have three aspects. Firstly, the multi-phase fluids modeling, which is used to simulate the interaction and flow between fluids. Then the surface reconstruction method for multi-phase flow is proposed to solve the problem of multi-phase interface construction. Secondly, the physical quantities of gas - liquid coupling are calculated by the interaction of gas particles with fluid particles, then we model the coupling phenomena of gas-liquid. Finally, we handle the interaction of fluid with rigid body as well as fluid with deformable body, and sample the surface of a rigid body. Then we create interaction model of surface particles with fluid particles and implement fluid-solid coupling in a unified framework of particles. The research of this project is expected to solve the key problems of multi-phase flow and interactive phenomena simulation, which has theoretical and practical significance in the fields of film and television special effects, digital entertainment and virtual reality.

面向复杂场景的流体模拟涉及多种介质及它们之间的交互问题，这造成流体真实感模拟的困难。为此，本项目面向多相流场景，研究流体交互现象的三维建模方法，解决多相流-流交互建模、气体-液体耦合建模、流固耦合及边界处理等问题，力图构建逼真的流体交互现象的动画效果。本项目的研究内容主要有三方面：首先，对多相流体-流体交互进行建模，该模型主要用来模拟流体与流体间相互作用及流动情况，然后研究面向多相流体的表面重构方法，解决多相界面构造问题；其次，通过气体粒子与流体粒子的交互来构建气-液相之间各物理量的计算式，然后对气-液相各种耦合现象进行建模；最后，处理流体与刚体及可变形体的交互问题，对刚体表面进行采样，建立刚体表面粒子与流体粒子的交互模型，在统一的粒子框架下实现流固耦合效果。本项目的研究有望解决多相流场景交互现象模拟的相关关键问题，对影视特技、数字娱乐以及虚拟现实等领域具有重要的理论意义和应用价值。

面向复杂场景的流体模拟涉及多种介质建模及交互问题，本项目以多相流体交互动画为主要研究对象，提出了多相流体物理模拟的相关方法。结合多相流动力学特性，构建基于拉格朗日视角的物质离散化模型；通过提升多相物质交互界面处高阶数值计算精度，丰富了流体动画交互元素与表达能力，增强了多相流模拟的真实感效果和计算效率。主要研究内容包括：.1）多相流体交互物理建模：针对传统SPH方法在高密度比非均质流体界面的数值近似误差问题，提出了基于体积通量的无散度光滑粒子流体动力学隐式积分及各向异性表面重构方法，提升了高密度比多相流体交互模拟的稳定性与迭代收敛效率。.2）气-液耦合现象模拟：针对固体与高速运动的流体发生碰撞拽入气泡、产生泡沫等现象，提出了统一多尺度气泡模拟方案，实现了高效大规模气-液交互效果。.3）流体动画湍流效果增强方法：针对多相流环境下SPH方法在流体模拟中所存在的数值耗散导致的流体动态细节丢失问题，提出了基于流函数的涡度恢复模型，实现稳定可控的增强湍流细节增强。.4）流固耦合动画模型：针对传统流固耦合方法在处理多相流场景下所产生的不稳定现象，基于SPH体积近似原理提出加权光滑核下的镜像刚体粒子耦合方案，实现稳定多相流-固交互效果。.项目形成的研究成果在Computer Graphics Forum、The Visual Computer、计算机科学技术学报(英文版)等重要期刊和SIGGRAPH、VR、SCA、CGI等著名学术会议发表论文15篇，其中9篇被SCI收录，4篇CCF A会议论文，2篇CCF B期刊论文，3篇CCF C期刊论文，1篇获CGI国际会议最佳论文奖。