Hybrid Reynolds-Averaged / Large-Eddy Simulations of Ramped-Cavity and Compression Ramp Flow-fields

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Title: Hybrid Reynolds-Averaged / Large-Eddy Simulations of Ramped-Cavity and Compression Ramp Flow-fields
Author: Fan, Thomas Chen-Chuan
Advisors: Dr. Jack R. Edwards, Committee Chair
Abstract: A procedure for simulating wall-bounded,separated flows utilizing hybrid large-eddy / Reynolds- Averaged strategies is presented in this work. Following the zonal concept, the proposed hybrid method uses a distance-dependent blending function to shift the turbulence closure from Menter's two-equation model near wall surfaces to a one-equation subgrid model away from walls. The code is parallelized using domain-decomposition / MPI message-passing methods and is optimized for operation on the 720 processor IBM SP-2 at the North Carolina Supercomputing Center. The capabilities of the hybrid method are examined on two benchmark flows: a ramped-cavity flow that is representative of the internal flow field of a high speed propulsion device, and a compression ramp flow that features the classical problem of a shock wave / boundary layer interaction. Results indicate that the hybrid method provides generally good predictions for the ramped-cavity configuration, but less satisfactory predictions for the compression ramp configuration. Nevertheless, the strength of the hybrid method in capturing the recovery of the boundary layer downstream of reattachment is found in both cases, and it is a major improvement over the simulations produced by RANS alone. The weaknesses in simulating the compression ramp flow are also discussed and possible remedies are provided for further investigation in the future.
Date: 2002-07-24
Degree: MS
Discipline: Aerospace Engineering
URI: http://www.lib.ncsu.edu/resolver/1840.16/916


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