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Simulation of receptivity and induced transition from discrete roughness elements

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journal contribution
posted on 08.10.2015, 10:51 authored by Vinan I. Mistry, Gary PageGary Page, Jim McGuirk
Dordrecht Simulations have been carried out to predict the receptivity and growth of crossflow vortices created by Discrete Roughness Elements (DREs) The final transition to turbulence has also been examined, including the effect of DRE spacing and freestream turbulence. Measurements by Hunt and Saric (2011) of perturbation mode shape at various locations were used to validate the code in particular for the receptivity region. The WALE sub-grid stress (SGS) model was adopted for application to transitional flows, since it allows the SGS viscosity to vanish in laminar regions and in the innermost region of the boundary layer when transition begins. Simulations were carried out for two spanwise wavelengths: λ= 12mm (critical) and λ= 6mm (control) and for roughness heights (k) from 12 μm to 42 μm. The base flow considered was an ASU (67)-0315 aerofoil with 45 0 sweep at -2.9 0 incidence and with onset flow at a chord-based Reynolds number Re c= 2.4x10 6. For λ= 12mm results showed, in accord with the experimental data, that the disturbance amplitude growth rate was linear for k = 12 μm and 24 μm, but the growth rate was decreased for k = 36 μm Receptivity to λ= 6mm roughness showed equally good agreement with experiments, indicating that this mode disappeared after a short distance to be replaced by a critical wavelength mode. Analysis of the development of modal disturbance amplitudes with downstream distance showed regions of linear, non-linear, saturation, and secondary instability behaviour. Examination of breakdown to turbulence revealed two possible routes: the first was 2D-like transition (probably Tollmien-Schlichting waves even in the presence of crossflow vortices) when transition occurred beyond the pressure minimum; the second was a classical crossflow vortex secondary instability, leading to the formation of a turbulent wedge.

Funding

The authors would like to thank the Flight Physics Department at Airbus (Filton) for provision of supercomputer time and financial support of the project. The work was funded by UK EPSRC Grant GT/T11295. In addition some simulations have been carried out using HPC Midlands, which is funded by UK EPSRC Grant EP/K000063/1.

History

School

  • Aeronautical, Automotive, Chemical and Materials Engineering

Department

  • Aeronautical and Automotive Engineering

Published in

Flow, Turbulence and Combustion

Volume

95

Pages

301 - 334

Citation

MISTRY, V.I., PAGE, G.J. and MCGUIRK, J.J., 2015. Simulation of receptivity and induced transition from discrete roughness elements. Flow, Turbulence and Combustion, 95 (2), pp. 301-334.

Publisher

© Springer Science+Business Media

Version

AM (Accepted Manuscript)

Publisher statement

This work is made available according to the conditions of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) licence. Full details of this licence are available at: https://creativecommons.org/licenses/by-nc-nd/4.0/

Publication date

2015-08-21

Notes

The final publication is available at Springer via http://dx.doi.org/10.1007/s10494-015-9636-y

ISSN

1386-6184

eISSN

1573-1987

Language

en