Honors Theses

Advisor

C. Taber Wanstall, Ph.D.

Department

Mechanical and Aerospace Engineering

Publication Date

4-23-2025

Document Type

Honors Thesis

Abstract

This study experimentally investigates the effect of wavy walls on the second-mode boundary-layer instability in the hypersonic regime. The experiments were performed in the Air Force Research Laboratory’s Mach-6 Ludwieg Wind Tunnel on flat-plate test articles. Two different flat-plate test articles were used: a smaller test article used in previous studies and one larger that was constructed for these specific experiments. Findings include the initial test results of the larger test article without a wavy-wall insert and results from three different wavy-wall samples taken using the smaller test article. The initial larger flat plate test results showed that the boundary-layer transition onset behavior varied between the fluctuating surface pressure power spectra measurements and the surface heat-flux measurements. The spectral measurements indicated transition onset upstream of the heat-flux measurements. The wavy-wall test results showed that the wavy-wall inserts shifted the second-mode frequencies lower. Additionally, the higher-amplitude wavy walls provided spectra that indicated a second-mode frequency locking tendency, which was shown to trend well with the freestream unit Reynolds number.

Permission Statement

This item is protected by copyright law (Title 17, U.S. Code) and may only be used for noncommercial, educational, and scholarly purposes.

Keywords

Undergraduate research

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