Roughness-induced instabilities at Mach 6: A combined numerical and experimental study

Bradley M. Wheaton, Matthew D. Bartkowicz, Pramod K Subbareddy, Steven P. Schneider, Graham V. Candler

Research output: Chapter in Book/Report/Conference proceedingConference contribution

26 Scopus citations

Abstract

To develop improved methods of transition prediction for isolated roughness based on the growth of disturbances in the roughness wake, the underlying instability mechanisms must first be understood. This paper presents a direct comparison of experimentally- observed and computed instabilities due to a cylindrical roughness in a boundary layer at Mach 6, to identify the dominant mechanism for transition. Direct numerical simulations allow a detailed analysis of the entire flow field, while experimental measurements discover the real flow physics and confirm the findings of the computations. For a large roughness height of 10.2 mm, an instability with a frequency near 21 kHz originates in the separation region upstream of the roughness. Unstable shear layers and horseshoe vortices appear to cause transition downstream of the roughness for this case. As the roughness height is reduced, there appears to be a change in the dominant instability mechanism.

Original languageEnglish (US)
Title of host publication41st AIAA Fluid Dynamics Conference and Exhibit
PublisherAmerican Institute of Aeronautics and Astronautics Inc.
ISBN (Print)9781600869471
DOIs
StatePublished - 2011
Event41st AIAA Fluid Dynamics Conference and Exhibit 2011 - Honolulu, HI, United States
Duration: Jun 27 2011Jun 30 2011

Publication series

Name41st AIAA Fluid Dynamics Conference and Exhibit

Conference

Conference41st AIAA Fluid Dynamics Conference and Exhibit 2011
CountryUnited States
CityHonolulu, HI
Period6/27/116/30/11

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