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The effect of flow confinement on laminar shockwave/boundary-layer interactions

The effect of flow confinement on laminar shockwave/boundary-layer interactions
The effect of flow confinement on laminar shockwave/boundary-layer interactions
Numerical work on shockwave/boundary-layer interactions (SBLIs) to date has largely focused on span-periodic quasi-2D configurations that neglect the influence lateral confinement has on the core flow. The present study is concerned with the effect of flow confinement on Mach 2 laminar SBLI in rectangular ducts. An oblique shock generated by a 2◦ wedge forms a conical swept SBLI with sidewall boundary layers before reflecting from the bottom wall of the domain. Multiple large regions of flow-reversal are observed on the sidewalls, bottom wall and at the corner intersection. The main interaction is found to be strongly three-dimensional and highly dependent on the geometry of the duct. Comparison to quasi-2D span-periodic simulations showed sidewalls strengthen the interaction by 31% for the baseline configuration with an aspect ratio of one. The length of the shock generator and subsequent trailing edge expansion fan position was shown to be a critical parameter in determining the central separation length. By shortening the length of the shock generator, modification of the interaction and suppression of the central interaction is demonstrated. Parametric studies of shock strength and duct aspect ratio were performed to find limiting behaviours. For the largest aspect ratio of four, three-dimensionality was visible across 30% of the span width away from the wall. The topology of the three-dimensional separation is shown to be similar to ‘owl-like’ separations of the first kind. Reflection of the initial conical swept SBLIs is found to be the most significant factor determining the flow structures downstream of the main interaction.
SBLI, flow confinement, three-dimensional separation
0022-1120
Lusher, David
dd681c9e-ceae-409b-8153-8248c13a18e5
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97
Lusher, David
dd681c9e-ceae-409b-8153-8248c13a18e5
Sandham, Neil
0024d8cd-c788-4811-a470-57934fbdcf97

Lusher, David and Sandham, Neil (2020) The effect of flow confinement on laminar shockwave/boundary-layer interactions. Journal of Fluid Mechanics. (In Press)

Record type: Article

Abstract

Numerical work on shockwave/boundary-layer interactions (SBLIs) to date has largely focused on span-periodic quasi-2D configurations that neglect the influence lateral confinement has on the core flow. The present study is concerned with the effect of flow confinement on Mach 2 laminar SBLI in rectangular ducts. An oblique shock generated by a 2◦ wedge forms a conical swept SBLI with sidewall boundary layers before reflecting from the bottom wall of the domain. Multiple large regions of flow-reversal are observed on the sidewalls, bottom wall and at the corner intersection. The main interaction is found to be strongly three-dimensional and highly dependent on the geometry of the duct. Comparison to quasi-2D span-periodic simulations showed sidewalls strengthen the interaction by 31% for the baseline configuration with an aspect ratio of one. The length of the shock generator and subsequent trailing edge expansion fan position was shown to be a critical parameter in determining the central separation length. By shortening the length of the shock generator, modification of the interaction and suppression of the central interaction is demonstrated. Parametric studies of shock strength and duct aspect ratio were performed to find limiting behaviours. For the largest aspect ratio of four, three-dimensionality was visible across 30% of the span width away from the wall. The topology of the three-dimensional separation is shown to be similar to ‘owl-like’ separations of the first kind. Reflection of the initial conical swept SBLIs is found to be the most significant factor determining the flow structures downstream of the main interaction.

Text
Lusher_JFM_2020 - Accepted Manuscript
Restricted to Repository staff only until 21 October 2020.
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More information

Accepted/In Press date: 21 April 2020
Keywords: SBLI, flow confinement, three-dimensional separation

Identifiers

Local EPrints ID: 439727
URI: http://eprints.soton.ac.uk/id/eprint/439727
ISSN: 0022-1120
PURE UUID: 99d89738-5352-48c8-a2e9-d74fde5ca201
ORCID for David Lusher: ORCID iD orcid.org/0000-0001-8874-5290
ORCID for Neil Sandham: ORCID iD orcid.org/0000-0002-5107-0944

Catalogue record

Date deposited: 30 Apr 2020 16:34
Last modified: 29 Jul 2020 01:54

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