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A mechanism for control of turbulent separated flow in rectangular diffusers

Published online by Cambridge University Press:  18 October 2011

Hayder Schneider ,
Dominic A. Von Terzi ,
Hans-Jörg Bauer  and
Wolfgang Rodi
Hayder Schneider*
Affiliation:
Institute for Thermal Turbomachinery, Karlsruhe Institute of Technology, Kaiserstraße 12, 76128 Karlsruhe, Germany
Dominic A. Von Terzi
Affiliation:
Institute for Thermal Turbomachinery, Karlsruhe Institute of Technology, Kaiserstraße 12, 76128 Karlsruhe, Germany Aeronautics Department, Imperial College London, Prince Consort Road, London SW7 2AZ, UK
Hans-Jörg Bauer
Affiliation:
Institute for Thermal Turbomachinery, Karlsruhe Institute of Technology, Kaiserstraße 12, 76128 Karlsruhe, Germany
Wolfgang Rodi
Affiliation:
Institute for Hydromechanics, Karlsruhe Institute of Technology, Kaiserstraße 12, 76128 Karlsruhe, Germany
*
†Email address for correspondence: [email protected]
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Abstract

The turbulent separated flow through an asymmetric diffuser with and without manipulation of incoming turbulence-driven mean secondary vortices (MSVs) from a rectangular duct is investigated by large-eddy simulations. The simulations carried out for two diffuser geometries reveal that by introducing a small amount of mean-flow kinetic energy via the MSVs into the flow, the complex three-dimensional separation behaviour and pressure recovery can be effectively controlled. Manipulated MSVs were found to enhance cross-sectional transport of high-momentum fluid, which determined the location, shape, and size of the separation bubble. The integral effect was a delay or expedition in the onset of separation. This change strongly affected the conversion of mean-flow kinetic energy to pressure, in particular for the front part of the diffuser. In addition, a substantial reduction in total pressure loss could be achieved. The manipulation of the MSVs is an efficient mechanism for performance enhancement in the cases investigated. The results have important implications for both control and statistical modelling of turbulent separated flow in rectangular diffusers.

JFM classification

Flow Control: Flow Control Turbulent Flows: Turbulent Flows
Type
Papers
Information
Journal of Fluid Mechanics , Volume 687 , 25 November 2011 , pp. 584 - 594
Copyright
Copyright © Cambridge University Press 2011

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Footnotes

‡

Current address: GE Global Research, 85748 Garching/Munich, Germany

References

1. Cherry, E. M., Elkins, C. J. & Eaton, J. K. 2008 Geometric sensitivity of three-dimensional separated flows. Intl J. Heat Fluid Flow 29 (3), 803–811.CrossRefGoogle Scholar
2. Demuren, A. O. & Rodi, W. 1984 Calculation of turbulence-driven secondary motion in non-circular ducts. J. Fluid Mech. 140, 189–222.CrossRefGoogle Scholar
3. Grundmann, S., Sayles, E. & Eaton, J. 2010 Sensitivity of an asymmetric 3D diffuser to plasma-actuator induced inlet condition perturbations. Exp. Fluids 1–15.Google Scholar
4. Hinterberger, C. 2004 Dreidimensionale und tiefengemittelte Large-Eddy-Simulation von Flachwasserströmungen. PhD thesis, University of Karlsruhe, Karlsruhe, Germany.Google Scholar
5. Jakirlić, S., Kadavelil, G., Kornhaas, M., Schäfer, M., Sternel, D. C. & Tropea, C. 2010 Numerical and physical aspects in LES and hybrid LES/RANS of turbulent flow separation in a 3-D diffuser. Intl J. Heat Fluid Flow 31 (5), 820–832.CrossRefGoogle Scholar
6. Jakirlić, S., Kadavelil, G., Sirbubalo, S., von Terzi, D. A., Breuer, M. & Borello, D. 2011 14th ERCOFTAC SIG15 Workshop on Refined Turbulence Modelling. ERCOFTAC Bulletin 85.Google Scholar
7. Ohlsson, J., Schlatter, P., Fischer, P. F. & Henningson, D. S. 2010 Direct numerical simulation of separated flow in a three-dimensional diffuser. J. Fluid Mech. 650, 307–318.CrossRefGoogle Scholar
8. Schneider, H., von Terzi, D. A., Bauer, H.-J. & Rodi, W. 2010 Reliable and accurate prediction of three-dimensional separation in asymmetric diffusers using Large-Eddy Simulation. J. Fluids Engng 132 (3) 031101.CrossRefGoogle Scholar
9. Schneider, H., von Terzi, D. A., Bauer, H. -J. & Rodi, W. 2011 Impact of secondary vortices on separation dynamics in 3D asymmetric diffusers. In Direct and Large-Eddy Simulation VIII (ed. Kuerten, H., Geurts, B., Armenio, V. & Fröhlich, J. ), pp. 443–448. Springer.CrossRefGoogle Scholar
10. von Terzi, D., Schneider, H. & Bauer, H.-J. 2011 The impact of secondary mean vortices on turbulent separation in 3D diffusers. In High Performance Computing in Science and Engineering ’10 (ed. Nagel, W. E., Kröner, D. B. & Resch, M. M. ), pp. 339–352. Springer.Google Scholar
11. von Terzi, D., Schneider, H. & Fröhlich, J. 2010 Diffusers with three-dimensional separation as test bed for hybrid LES/RANS methods. In High Performance Computing in Science and Engineering ’09 (ed. Nagel, W. E., Kröner, D. B. & Resch, M. M. ), pp. 355–368. Springer.CrossRefGoogle Scholar