Roughness-Induced Transition in a Supersonic Boundary Layer

Direct numerical simulation is used to investigate the transition induced by three-dimensional isolated roughness elements in a supersonic boundary layer at a freestream Mach number of 3.5. Simulations are performed for two different configurations: one is a square planform roughness element, and th...

Full description

Saved in:
Bibliographic Details
Published in:AIAA journal 2016-08, Vol.54 (8), p.2322-2337
Main Authors: Balakumar, P, Kegerise, Michael
Format: Article
Language:English
Subjects:
Amplitudes
Boundary layer transition
Computational fluid dynamics
Direct numerical simulation
Fluid flow
Mach number
Mathematical analysis
Planforms
Roughness
Supersonic boundary layers
Vortices
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Direct numerical simulation is used to investigate the transition induced by three-dimensional isolated roughness elements in a supersonic boundary layer at a freestream Mach number of 3.5. Simulations are performed for two different configurations: one is a square planform roughness element, and the other is a diamond planform roughness element. The mean flow calculations show that the roughness element induces counter-rotating streamwise vortices downstream of the roughness element. These vortices persist for a long distance downstream, lift the low-momentum fluid from the near-wall region, and place it near the outer part of the boundary layer. This forms highly inflectional boundary-layer profiles. These observations agree with recent experimental observations. The receptivity calculations show that the amplitudes of the mass-flux fluctuations near the neutral point for the diamond-shaped roughness element are the same as the amplitude of the acoustic disturbances. They are three times smaller for the square-shaped roughness element.
ISSN:0001-1452
1533-385X
DOI:10.2514/1.J054632