Hybrid Large-Eddy Simulation/Reynolds-Averaged Navier-Stokes Methods and Predictions for Various High-Speed Flows

turbulence modeling;turbulence;cfd;channel;shock trains;injection;hybrid LES/RANS;LES/RANS;RANS;LES;computational fluid dynamics

Boles, John Arthur ; Jack Edwards, Committee Chair,Hassan Hassan, Committee Member,Hong Luo, Committee Member,Fred DeJarnette, Committee Member,Boles, John Arthur ; Jack Edwards ; Committee Chair ; Hassan Hassan ; Committee Member ; Hong Luo ; Committee Member ; Fred DeJarnette ; Committee Member

University:North Carolina State University

关键词: turbulence modeling;    turbulence;    cfd;    channel;    shock trains;    injection;    hybrid LES/RANS;    LES/RANS;    RANS;    LES;    computational fluid dynamics;   

Others  :  https://repository.lib.ncsu.edu/bitstream/handle/1840.16/3428/etd.pdf?sequence=1&isAllowed=y

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【 摘 要 】

Hybrid Large Eddy Simulation/Reynolds-Averaged Navier-Stokes (LES/RANS) simulations of several high-speed flows are presented in this work. The solver blends a Menter BSL two-equation model for the RANS part of the closure with a Smagorisnky sub-grid model for the LES component. The solver uses a flow-dependent blending function based on wall distance and a modeled form of the Taylor micro-scale to transition from RANS to LES. Turbulent fluctuations are initiated and are sustained in the inflow region using a recycling/rescaling technique. A new multi-wall recycling/rescaling technique is described and tested. A spanwise-shifting method is introduced that is intended to alleviate unphysical streamwise streaks of high- and low-momentum fluid that appear in the time-averaged solution due to the recycling procedure. Simulations of sonic injection of air, helium and ethylene into a Mach 2 cross-flow of air are performed. Also, simulations of Mach 5 flow in a subscale inlet/isolator configuration with and without back-pressuring are performed. Finally, a Mach 3.9 flow through a square duct is used as an initial test case for the new multi-wall recycling and rescaling method as well as a multi-wall shifting procedure. A discussion of the methods, implementation and results of these simulations is included.