53rd NIA CFD Seminar Webcast

Topic: Numerical Simulations of General Conservation Laws Using the Space-Time Conservative CESE Method

Date: Tuesday, September 09, 2014

Time: 11:00am-noon (EDT)

Room: NIA, Rm137

Speaker: Chau-Lyan Chang

Speaker Bio: Dr. Chau-Lyan Chang is a research scientist from the Computational AeroSciences Branch at NASA Langley Research Center. His primary research interest is in unstructured mesh CFD methods and code development. He also works on numerical computations of boundary layer stability and transitions. He actively maintains LASTRAC software and interacts with users from academia and industry.

Abstract: Governing equations of most engineering disciplines can be written as general conservation laws by enforcing mass, momentum, and energy balances. Modern computational methods are devised to provide accurate solutions to these conservation laws in the discretized space. The space-time conservation element solution element (CESE) method introduced in 1990s is a numerical framework for general conservation laws designed to provide discretized solutions in the space-time domain with considerations to ensure accuracy and robustness. The CESE method is constructed based on a non-dissipative, space time inversion invariant core scheme. Numerical dissipations are added as required. Discretized equations for dependent variables and high derivatives are formulated by enforcing both local and global conservations. It can be shown that fundamental quantities such as mass, momentum, and energy are strictly conserved both in the local conservation elements as well as the entire computational domain. To handle solutions with discontinuities, the integration volumes have interfaces that only encompass the smooth regions where solution polynomials are valid. With these constructs, the CESE numerical framework is free of ad-hoc reconstructions of physical quantities associated with interfacial discontinuity or approximations of kinetic energy. This talk discusses the fundamental concepts and development of the CESE framework with primary focus on 3D Navier-Stokes computations. High fidelity simulations of problems with multiple temporal/spatial-scales and physics are tackled with time accurate local time-stepping and high-order frameworks for unstructured meshes. Applications of the CESE method in other disciplines outside of NASA will be briefly discussed.

Additional information, including the webcast link, can be found at the NIA CFD Seminar website, which is temporarily located at

http://www.hiroakinishikawa.com/niacfds/index.html