Eric T. Fick

Date of Award

12-1995

Document Type

Thesis

Degree Name

Master of Science

Department

Department of Aeronautics and Astronautics

First Advisor

Thomas Buter, PhD

Second Advisor

Rodney Bowersox, PhD

Abstract

Mach 2.9 boundary layer flow (Re/m ≈ 1.75x107) under the influence of mild pressure gradients is studied numerically. Baldwin-Lomax and k - ω turbulence models are incorporated into a cell centered finite volume flow solver and the results are compared with hot wire anemometry and Laser Doppler Velocimetry (LDV) measurements obtained for the same geometries in the AFIT Mach 2.9 wind tunnel. Agreement between the present simulations obtained with the k - ω turbulence model and experimental velocity profiles is excellent in all test sections. Nondimensional turbulent shear stress predictions closely match experimental data in the flat plate and adverse pressure gradient sections while slightly over predicting this quantity in the favorable pressure gradient region. Favorable pressure gradients are found to stabilize the flow field, resulting in increased boundary layer thickness and reduced turbulent and wall shear stress distributions. Additionally, the presence of a favorable pressure gradient is found to diminish the effects of variations in upstream boundary condition specification. Adverse pressure gradients are found to destabilize the flow field, resulting in increases in the turbulent shear stress, turbulent kinetic energy, and wall shear stress. Upstream effects are found to play a major role in adverse pressure gradient flowfield development. Flow field features are predicted more accurately with the k - ω model than with the Baldwin-Lomax model.

AFIT Designator

AFIT-GAE-ENY-95D-10

DTIC Accession Number

ADA325879

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