Effects of Surface Roughness on Shock-Wave/Turbulent Boundary-Layer Interaction at Mach 4 over a Hollow Cylinder Flare Model

Matt Garcia; Eugene N. A. Hoffman; Elijah J. LaLonde; Christopher S. Combs; Mason Pohlman; Cary Smith; Mark T. Gragston; John D. Schmisseur

doi:10.3390/fluids7090286

Fluids (Aug 2022)

Effects of Surface Roughness on Shock-Wave/Turbulent Boundary-Layer Interaction at Mach 4 over a Hollow Cylinder Flare Model

Matt Garcia,
Eugene N. A. Hoffman,
Elijah J. LaLonde,
Christopher S. Combs,
Mason Pohlman,
Cary Smith,
Mark T. Gragston,
John D. Schmisseur

Affiliations

Matt Garcia: Department of Mechanical Engineering, Margie and Bill Klesse College of Engineering and Integrated Design, The University of Texas at San Antonio, San Antonio, TX 78249, USA
Eugene N. A. Hoffman: Department of Mechanical Engineering, Margie and Bill Klesse College of Engineering and Integrated Design, The University of Texas at San Antonio, San Antonio, TX 78249, USA
Elijah J. LaLonde: Department of Mechanical Engineering, Margie and Bill Klesse College of Engineering and Integrated Design, The University of Texas at San Antonio, San Antonio, TX 78249, USA
Christopher S. Combs: Department of Mechanical Engineering, Margie and Bill Klesse College of Engineering and Integrated Design, The University of Texas at San Antonio, San Antonio, TX 78249, USA
Mason Pohlman: Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee Space Institute, Tullahoma, TN 37388, USA
Cary Smith: Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee Space Institute, Tullahoma, TN 37388, USA
Mark T. Gragston: Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee Space Institute, Tullahoma, TN 37388, USA
John D. Schmisseur: Department of Mechanical, Aerospace, and Biomedical Engineering, The University of Tennessee Space Institute, Tullahoma, TN 37388, USA

DOI: https://doi.org/10.3390/fluids7090286
Journal volume & issue: Vol. 7, no. 9
p. 286

Abstract

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Although it is understood that surface roughness can impact boundary layer physics in high-speed flows, there has been little research aimed at understanding the potential impact of surface roughness on high-speed shock-wave/boundary-layer interactions. Here, a hollow cylinder flare model was used to study the potential impact of distributed surface roughness on shock-wave/boundary-layer interaction unsteadiness. Two surface conditions were tested—a smooth steel finish with an average roughness of 0.85 μm and a rough surface (3K carbon fiber) with an average roughness value of 9.22 μm. The separation shock foot from the shock-wave/boundary-layer interaction on the hollow cylinder flare was tracked by analyzing schlieren images with a shock tracking algorithm. The rough surface increased boundary layer thickness by approximately a factor of 10 compared to the smooth case, significantly altering the interaction scaling. Despite normalizing results, based on this boundary layer scaling, the rough surface case still exhibited mean shock foot positions further upstream more than the smooth surface case. Power spectra of the unsteady shock foot location data demonstrated that the rough surface case exhibited unsteady motion with attenuated energy relative to the smooth-wall case.

Published in Fluids

ISSN: 2311-5521 (Online)
Publisher: MDPI AG
Country of publisher: Switzerland
LCC subjects: Science: Physics: Heat: Thermodynamics; Science: Physics: Descriptive and experimental mechanics
Website: http://www.mdpi.com/journal/fluids

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