GAMES Webinar 2021 – 182期(仿真模拟专题) | 刘树森 (中国学院软件研究所)， Yunxin Sun (ETH Zurich)
【GAMES Webinar 2020-182期】(仿真模拟专题)
报告题目：Adapted SIMPLE Algorithm for Incompressible SPH Fluids with a Broad Range Viscosity
In simulating viscous incompressible SPH fluids, incompressibility and viscosity are typically solved in two separate stages. However, the interference between pressure and shear forces could cause the missing of behaviors that include preservation of sharp surface details and remarkable viscous behaviors such as buckling and rope coiling. To alleviate this problem, we introduce for the first time the semi-implicit method for pressure linked equations (SIMPLE) into SPH to solve incompressible fluids with a broad range viscosity. We propose to link incompressibility and viscosity solvers, and impose incompressibility and viscosity constraints iteratively to gradually remove the interference between pressure and shear forces. Compared to state-of-the-art methods, our method not only produces realistic viscous behaviors, but is also better at preserving sharp surface details.
He is working toward the PhD degree at the State Key Laboratory of Computer Science, Institute of Software, Chinese Academy of Sciences, advised by professor Wang Wencheng and associate professor He Xiaowei. His research interests include computer graphics and physical-based simulation.
报告嘉宾2：Yunxin Sun (ETH Zurich)
报告题目：Effecitive time step restrictions for explicit MPM simulation
Time steps for explicit MPM simulation in computer graphics are often selected by trial and error due to the challenges in automatically selecting stable time step sizes. In this talk, we will introduce a time integration scheme that uses time step restrictions that take into account forces, collisions, and even grid‐to‐particle transfers calculated near the end of the time step. This scheme leverages a novel set of restrictions that allow a time step to be selected that is stable, efficient to compute, and not too far from optimal. Firstly, we derive the general solution for the sound speed in nonlinear isotropic hyperelastic materials, which we use to enforce the classical CFL time step restriction. Secondly, we identify a single‐particle instability in explicit MPM integration and propose a corresponding time step restriction in the fluid case. We also propose a reflection‐based boundary condition for domain walls that supports separation and accurate Coulomb friction while preventing particles from penetrating the domain walls.
Yunxin Sun is currently a master’s student in Computer Science at ETH Zurich. Before that, he obtained his bachelor’s degree in software engineering at Tongji University, Shanghai, China. During his undergraduate studies, he was interested in physics-based simulation, human-computer interaction, and computational methods for medical images. Recently, he is also interested in systems and programming language support for graphics systems, and computer systems in general.
GAMES主页的“使用教程”中有 “如何观看GAMES Webinar直播？”及“如何加入GAMES微信群？”的信息；