Effect of Mach number on the structure of turbulent spots
Effect of Mach number on the structure of turbulent spots
Direct numerical simulations have been performed to study the dynamics of isolated turbulent spots in compressible isothermal-wall boundary layers. Results of a bypass transition scenario at Mach 2, 4 and 6 are presented. At all Mach numbers the evolved spots have a leading-edge overhang, followed by a turbulent core and a calmed region at the rear interface. The spots have an upstream-pointing arrowhead shape when visualized by near-wall slices, but a downstream-pointing arrowhead in slices away front the wall. The lateral spreading of the spot decreases substantially with the Mach number, consistent with a growth mechanism based on the instability of lateral shear layers. Evidence for a supersonic (Mach) mode substructure is found in the Mach 6 case, where coherent spanwise structures are observed under the spot overhang region.
boundary-layer-flow, simulation, transition, laminar
225-234
Krishnan, L.
4eb5cfc3-d3e2-474d-a63b-e1f80de54bf6
Sandham, N.D.
0024d8cd-c788-4811-a470-57934fbdcf97
2006
Krishnan, L.
4eb5cfc3-d3e2-474d-a63b-e1f80de54bf6
Sandham, N.D.
0024d8cd-c788-4811-a470-57934fbdcf97
Krishnan, L. and Sandham, N.D.
(2006)
Effect of Mach number on the structure of turbulent spots.
Journal of Fluid Mechanics, 566, .
(doi:10.1017/S0022112006002412).
Abstract
Direct numerical simulations have been performed to study the dynamics of isolated turbulent spots in compressible isothermal-wall boundary layers. Results of a bypass transition scenario at Mach 2, 4 and 6 are presented. At all Mach numbers the evolved spots have a leading-edge overhang, followed by a turbulent core and a calmed region at the rear interface. The spots have an upstream-pointing arrowhead shape when visualized by near-wall slices, but a downstream-pointing arrowhead in slices away front the wall. The lateral spreading of the spot decreases substantially with the Mach number, consistent with a growth mechanism based on the instability of lateral shear layers. Evidence for a supersonic (Mach) mode substructure is found in the Mach 6 case, where coherent spanwise structures are observed under the spot overhang region.
Text
effect_of_mach_number_on_the_structure_of_turbulent_spots.pdf
- Version of Record
More information
Published date: 2006
Keywords:
boundary-layer-flow, simulation, transition, laminar
Organisations:
Aerodynamics & Flight Mechanics
Identifiers
Local EPrints ID: 43016
URI: http://eprints.soton.ac.uk/id/eprint/43016
ISSN: 0022-1120
PURE UUID: a4b8cd7c-118a-4d1c-a325-490f94ddfeff
Catalogue record
Date deposited: 08 Jan 2007
Last modified: 16 Mar 2024 03:03
Export record
Altmetrics
Contributors
Author:
L. Krishnan
Author:
N.D. Sandham
Download statistics
Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.
View more statistics