Date of Award

Fall 2001

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Aerospace Engineering

Committee Director

Osama A. Kandil

Committee Member

Robert L. Ash

Committee Member

Brett Newman

Call Number for Print

Special Collections; LD4331.E535 Y68 2001

Abstract

Universal Space Line (USL) is interested in developing an aerospace vehicle that flies at very high angles of attack (AOAs) through wide range of Mach numbers. The basic model configuration is called SC-X model, which consists of a blunt cone and a cylindrical afterbody. A structured O-type grid was generated for this model by numerically solving elliptic partial differential equations. The three-dimensional, unsteady, compressible, Reynolds-averaged Navier-Stokes equations coupled with Spalart-Allmaras turbulence model were used as computational tool to investigate the transonic and supersonic flows around the SC-X model pitched at AOA of 45°. For the code validation, this computational solver was used to investigate the subsonic flow regime around SC-X model and the results were shown in good agreement with that of the unstructured CFD solver NSU3D. In the transonic flow regime, the solutions predicted the full development of the unsteady, asymmetric flow separation. The time history of large oscillations of lift, drag and side force coefficients reflects the transonic flow characteristics. The transverse-shock interaction and shock-shifting phenomena were captured at the cone-cylinder juncture. In supersonic flow regime, the periodic vortex shedding was captured. The results show a periodic change of side force coefficient with respect to time. The lift and drag coefficients converge to steady values after the transient period. The large drag force coefficient is attributed to the strong bow shock appearing ahead of the body nose. The flow control effectiveness of a pair of side strakes near the body nose of SC-X model was investigated in transonic flow regime. It was shown that the asymmetric flow separation was suppressed due to the strong strake-generated vortices. Compared with no-strake case, the side force coefficient was largely reduced. The amplitude of lift and drag coefficient oscillations with respect to time was also reduced.

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DOI

10.25776/9mrp-r167

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