Journal of Applied Mechanical Engineering

Computational fluid dynamics based on the unified coordinates

Global Summit and Expo on Fluid Dynamics & Aerodynamics

August 15-16, 2016 London, UK

W H Hui

Hong Kong University of Science and Technology, Hong Kong
University of Waterloo, Canada

Posters & Accepted Abstracts: J Appl Mech Eng

Abstract:

Computational fluid dynamics (CFD) uses large scale numerical computation to solve problems of fluid flow. Traditionally, it uses either the Eulerian or the Lagrangian coordinate system. These two systems are numerically non-equivalent, but each has its advantages as well as drawbacks. A unified coordinate system (UC) has recently been developed which combines the advantages of both Eulerian and Lagrangian systems, while avoiding their drawbacks. This talk gives a systematic discussion on CFD using the unified coordinates. It will be shown that: (1) The governing equations of fluid flow in any moving coordinates can be written as a system of closed conservation PDEs, thus enabling correct capturing of shocks; (2) the system of Lagrangian gas dynamics equations is written in conservation PDE form for the first time, providing the foundation for developing Lagrangian schemes as moving mesh schemes in Eulerian space; (3) the Lagrangian gas dynamics equations in 2-D and 3-D are shown to be non-equivalent to the Eulerian ones, theoretically. Computationally, (4) the UC is shown to be superior to both Eulerian and Lagrangian systems in that, contact discontinuities are resolved sharply without mesh tangling; (5) the UC avoids the tedious and time-consuming task of mesh generation in the Eulerian method for flow past a body; the mesh in UC is automatically generated by the flow; (6) the UC represents a new moving-mesh method, where the effects of moving mesh on the flow are fully accounted for. Many examples are given to demonstrate these properties of the UC.

Biography :

Email: whhui@ust.hk