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Prof. Kun Xu (徐昆 教授)
Chair Professor, Department of Mathematics
Hong Kong University of Science and Technology
Email: makxu@ust.hk |
Abstract: All fluid dynamic equations have their intrinsic modeling scales, such as the mean free path scale of the Boltzmann equation and the hydrodynamic scale of the Navier-Stokes equations. The current computational fluid dynamics (CFD) is actually a direct discretization of these PDEs. Even with limited mesh size, the CFD targets to recover the exact solution of the PDE as mesh size and time step approaching to zero. Under such a CFD methodology, the best result is to luckily get the exact solution of the governing equation. But, the flow physics is still limited by the modeling scale of the original governing equation. In reality, due to the limited cell resolution, we can never get the exact solution of these equations, and the limited mesh size and time step seem to introduce numerical errors only.
In a discretized space with limited cell resolution, the aim of CFD should directly model and simulate the flow motion in the mesh size and time step scales. With the variation of the ratio between the mesh size and the local particle mean free path, a direct modeling should be able to capture the flow physics from the kinetic scale particle collision and transport to the hydrodynamic scale wave propagation. The unified gas kinetic scheme is constructed under such a direct modeling principle. A continuum spectrum of governing equations from the kinetic to the hydrodynamic scales can be recovered in the direct modeling CFD method.
报告人简介：徐昆, 香港科技大学数学系教授, 于1987年北京大学天体物理系毕业, 获得CUSPEA奖学金, 赴美国哥伦比亚大学攻读博士学位, 1993年到1996年在普林斯顿大学, 师从Jameson教授进行博士后研究。1996年到香港科技大学数学系工作, 主要从事基于气体动理论的计算流体力学方法研究, 是国际计算流体力学领域著名学者。目前担任International Journal of Computational Fluid Dynamics, Communications in Computational Physics 和Computers and Fluids杂志副主编。
Date&Time: April 17, 2014 (Thursday), 15:30 - 17:00
Location: No. 10 Meeting Room, Run Ze Jia Ye Hotel
