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Large Eddy Simulations of Micro-Vortex Generators for Shock Wave/Turbulent Boundary Layer Interaction

Principal Investigator: Julien Bodart, ISAE-SUPAERO, Université de Toulouse (France)
HPC Platform: JUQUEEN of JSC
Date published: January 2019
JSC Project ID: PRA097

The challenge

This project aims to investigate the influence of the height h and distance to the interaction d of microramp vortex generators (mVGs) placed upstream the interaction region in order to control the unsteady mechanisms and separation involved in a Shock Boundary Layer Interaction (SBLI). It follows a previous high-fidelity Large Eddy Simulations (LES) campaignon french national supercomputers (GENCI grant).

Why supercomputing power?

SBLI is a complex phenomenon that involves low frequency displacement of the shock foot. Relevant simulations of this problem therefore require an unsteady solver that has i) the ability to capture small turbulent structures, and ii) can provide short restitution time so that long time integration keeps the CPU cost manageable. The last point is essential to gather a sufficient number of statistical samples of the low frequency modes.

What are the findings/knowledge gained?

A first LES campaign focused on the influence of the distance d between the mVGs and the interaction region. In previous work d was a fixed distance upstream of the mVGs. We have considered a variation of this parameter while preserving the same height for the mVG, and identical flow conditions than the experimental work of to Wang et al. (2012). A second part of the proposed work has focused on the influence of the mVGs’ height h by considering lower/higher values considering a fixed separation distance of d = 16δv.

All the relevant flow properties such as unsteady pressure load, low frequency mode or flow topology around the recirculation zone and downstream the mVGs have been characterized, using several tools such as dynamic mode decomposition.

The comparison between the different cases have highlighted the dominating parameters towards the design of efficient control systems.

Large Eddy Simulations of Micro-Vortex Generators for Shock Wave/Turbulent Boundary Layer InteractionFigure 1 - Instantaneous visualization of the coherent structures in the wake of the mVGs by means of Q-criterion, coloured by velocity magnitude, for four different cases. Shock waves are displayed in light blue using iso-surfaces of dilatation.
Copyright: Université de Toulouse (France)


Large Eddy Simulations of Micro-Vortex Generators for Shock Wave/Turbulent Boundary Layer InteractionFigure 2 - Time-averaged skin friction lines for all cases. Black thick solid lines indicate the separation and reattachment lines. Red dotted solid lines show the iso contour of mean streamwise shear-stress 〈τ w,x 〉 = 0. Black triangle denotes the symmetry plane of the mVG, white triangles indicate the 25% span of the mVG and grey triangles show the location of the plane in-between the mVGs.
Copyright: Université de Toulouse (France)


Who did/will benefit from the insights gained? In what way?

This work provides a valuable addition to the literature. The numerical database is still being analysed and will be used to understand the control mechanisms of the mVGs. The objective is to extract leading order parameters to derive reduced order models that accurately reproduce the effects of the mVGs, in order to reduce the CPU cost for design optimization.

We also showed in the present study that optimization frameworks should not be limited to RANS modelling but instead include large eddy simulations.

On the application side and for higher TR levels, this database will help the aeronautical industry to design control device for supersonic applications.

Research Team

Julien Bodart, Arnaud Grébert, Stéphane Jamme, Laurent Joly

Publications

Grébert, A., Bodart, J., Jamme, S., & Joly, L. "Simulations of shock wave/turbulent boundary layer interaction with upstream micro vortex generators". International Journal of Heat and Fluid Flow, volume 72, p. 73–85, August 2018.

Grebert, A. "Simulation numérique aux grandes échelles du contrôle de l’interaction onde de choc/couche limite turbulente au moyen de micro générateurs de vortex" PhD thesis, December 2018

Talk given in the area of the project

Grébert, A., Bodart, J., Jamme, S., & Joly, L."Simulations of shock wave/turbulent boundary layer interaction with upstream micro vortex generators". In 10th International Symposium on Turbulence and Shear Flow Phenomena, Chicago (USA), July 2017.

Scientific Contact:

Arnaud Grebert, Julien Bodart
ISAE-SUPAERO
Departement Aerodynamique Energétique et Propulsion
10 avenue Edouard Belin, F-31400 Toulouse (France)
e-mail: name.surname [at] isae-supaero.fr

NOTE: This project was made possible by PRACE (Partnership for Advanced Computing in Europe) allocating a computing time grant on GCS HPC system JUQUEEN of the Jülich Supercomputing Centre.

JSC project ID: PRA097

January 2019