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Communication Dans Un Congrès Année : 2015

Direct Numerical Simulations of the Interaction between an Oblique Shock Wave and a Boundary Layer Developing Along a Flat Plate

Résumé

Interactions between shock waves and boundary layers (SWBLI) are encountered in many industrial applications dealing with supersonic flows (aircraft design, rocket nozzles...). If the shock is strong enough, those interactions may cause the boundary layer separation yielding dynamic loads, increased heat fluxes and pressure fluctuations. Even if the physics of SWBLI is not fully understood, it is well known that the separation zone and the reflected shock are subjected to a low-frequency streamwise motion spreading over several tenth of the boundary layer thickness. The origin of this motion is, however, not completely elucidated but several studies has linked it to the shedding of vortices in the mixing layer downstream of the separation [1-2] and a simple model has even been developed [3] to explain this unsteadiness. In addition, recent experiments conducted in the IUSTI supersonic wind tunnel have shown that the recirculation region is highly three-dimensional [4]. These 3D aspects have been related to two contrarotative vortices developing downstream of the shock. Several numerical simulations using LES have been performed for the same geometry, most of them with periodic conditions in the spanwise direction. While the results are in rather good agreement with the experimental data for a weak shock wave, these simulations have failed to capture the three-dimensional aspect of the separation for a 9.5 degrees shock generator angle, demonstrating that the lateral walls of the wind tunnel are, at least partially, responsible for the 3D modulations of the recirculating region [5]. The number of points being prohibitively high in the case of LES (or DNS) of the full-span wind tunnel with lateral walls, alternative solutions have been tested. For instance, Garnier [6] has computed the entire domain with SDES, an hybrid RANS/LES method and has found that effective section of the wind tunnel is reduced because of the lateral walls, leading to a strengthened interaction. This observation explains the discrepancy between the separation regions obtained experimentally and numerically. This study has also shown that highly unsteady secondary flows develop around the corner of the wind tunnel. No obvious connection between these oscillations and the motion of the separation region has been found.
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Dates et versions

hal-01629393 , version 1 (06-11-2017)

Identifiants

  • HAL Id : hal-01629393 , version 1

Citer

Guillaume Fournier, Mohamed Sellam, Amer Chpoun, Yann Fraigneau, Christian Tenaud. Direct Numerical Simulations of the Interaction between an Oblique Shock Wave and a Boundary Layer Developing Along a Flat Plate. 30th International Symposium on Shock Waves, Springer, Jul 2015, Tel Aviv, Israel. ⟨hal-01629393⟩
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