02-21-2017 | Yi Liu: Third-Order Inviscid and Second-Order Hyperbolic Navier-Stokes Solvers for Three-Dimensional Unsteady Inviscid and Viscous Flows

Title: 82nd NIA CFD Seminar: Third-Order Inviscid and Second-Order Hyperbolic Navier-Stokes Solvers for Three-Dimensional Unsteady Inviscid and Viscous Flows

Date: Tuesday, February 21, 2017

Time: 11:00am-noon (EST)

Room: NIA, Rm101

Speaker: Yi Liu, Senior Research Engineer, NIA

Link to view seminars: http://nia-mediasite.nianet.org/NIAMediasite100/Catalog/Full/d374119e838c48bc9e3126aea146ffa321

Abstract: We present third-order-inviscid implicit edge-based solvers for unsteady inviscid and viscous flows on unstructured tetrahedral grids. Steady third-order-inviscid solvers recently developed in NASA’s FUN3D code are extended to unsteady computations with implicit time-stepping schemes. The physical time derivative is discretized by a backward-difference formula, and incorporated into the third-order edge-base scheme as a source term. In the third-order edge-based scheme, the source term needs to be discretized in space by a special formula to preserve third-order accuracy. A very economical source discretization formula is derived, and the resulting unsteady third-order unstructured-grid scheme is made completely free from second derivative computations. Developed unsteady schemes are investigated and compared for some representative test cases for unsteady inviscid and viscous flows. Preliminary results are also presented for a basic study of exploring a more stable third-order time integration scheme.

Bio: Dr. Yi Liu graduated from Georgia Institute of Technology with a Ph.D degree in aerospace engineering in 2003. He also holds a M.E. from Beijing University of Aeronautics and Astronautics in Beijing, China. In 2004, he joined the National Institute of Aerospace after a one-year postdoctoral fellowship at Georgia Tech. He has previously served as a senior research engineer at NIA in the area of computational fluid dynamics (CFD) and multi-disciplinary analysis of rotorcraft configurations. He has conducted various research projects, including work in the areas of rotorcraft aerodynamic analysis and acoustic prediction; micro-air vehicle and flapping wing aerodynamics sponsored by ARL and NASA. Currently, he is conducting the research project of implementation of third-order edge-based scheme in NASA CFD solver FUN3D with collaboration of researchers at NASA LaRC-Computational Aero Sciences Branch.