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Computational modelling of separated flowaround a streamlined body at high incidence

Published online by Cambridge University Press:  04 July 2016

F.-S. Lien
Affiliation:
Mechanical Engineering Department UMIST, Manchester, UK
M. A. Leschziner
Affiliation:
Mechanical Engineering Department UMIST, Manchester, UK

Abstract

A computational study has been undertaken of 3D vortical separation from the curved surface of a prolate spheroid at high angle of attack (10° and 30°). Attention focuses on the predictive capabilities of a new variant of non-linear, low Re eddy-viscosity model and full second-moment closure, the latter coupled to a low Re k-ε Boussinesq-viscosity model which is applied to the semi-viscous near-wall region. The study demonstrates that both anisotropy-resolving formulations return very similar predictive performance which is in several respects superior to that achieved with the k-ε model based on the linear stress-strain relations. At the higher incidence angle, transition is free, and this is the source of considerable uncertainty in respect of the sensitivity of the predicted leeward flow to the location of transition. While none of the models is fundamentally capable of capturing natural transition, the ability of the non-linear model to suppress turbulence generation by irrotational straining at the windward impingement region, thereby preventing (bypass) transition by diffusion of turbulence from the freestream to the laminar boundary layer, is exploited to demonstrate that the sensitivity of the separated leeward flow to the location of transition is weak.

Type
Research Article
Copyright
Copyright © Royal Aeronautical Society 1997 

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References

1. Leschziner, M.A. Refined turbulence modelling for engineering flows, Computational Fluid Dynamics ’94, Wiley, 1994, pp 3346.Google Scholar
2. Shih, T.H., Zhu, J. and Lumley, J.L. A realisable Reynolds stress algebraic equation model, NASA TM-105993, 1993.Google Scholar
3. Craft, T.J., Launder, B.E. and Suga, K. A Non-linear eddy-viscosity model including sensitivity to stress anisotropy, Proc 10th Symp Turbulent Shear Flows, The Pennsylvania State University, 1995, pp 23.1923.24.Google Scholar
4. Meier, H.U., Kreplin, H.P., Landhauser, A. and Baumgarten, D. Mean velocity distributions in three-dimensional boundary layers, developing on a 1:6 prolate spheroid with artificial transition (α = 10°, U∞ = 55 ms-1, Cross Sections x0/2a = 0·48, 0·56, 0·64 and 0·73), DFVLR Report IB 222-84 A l l 1984.Google Scholar
5. Kreplin, H.P., Vollmers, H. and Meier, H.U. Wall shear stress measurements on an inclined prolate spheroid in the DFVLR 3 m x 3 m low speed wind tunnel, Göttingen, DFVLR Report IB 222-84 A 33, 1985.Google Scholar
6. Vatsa, V.N., Thomas, J.L. and Wedan, B.W. Navier-Stokes computations of prolate spheroids at angle of attack, J Aircr, 1989, 26, pp 986993.Google Scholar
7. Gee, K., Cummings, R.M. and Schiff, L.B. Turbulence model effects on separated flow about a prolate spheroid, AIAA J, 1992, 30, pp 655664.Google Scholar
8. Baldwin, B. and Lomax, H. Thin-layer approximation and algebraic model for separated turbulent flows, AIAA Paper 78-0257, 1978.Google Scholar
9. Johnson, D.A. and King, L.S. A new turbulence closure model for boundary layer flows with strong adverse pressure gradients and separation, AIAA Paper 84-0175, 1984.Google Scholar
10. Lien, F.S. and Leschziner, M.A. Computational modelling of 3D turbulent flow in S-diffuser and transition ducts, Engineering Turbulence Modelling and Measurements 2, Elsevier, 1993, pp 217228.Google Scholar
11. Gibson, M.M. and Launder, B.E. Ground effects on pressure fluctuations in the atmospheric boundary layer, J Fluid Mech, 1978, 86, pp 491511.Google Scholar
12. Wolfshtein, M.W. The velocity and temperature distribution in one-dimensional flow with turbulence augmentation and pressure gradient, Int J Heat Mass Trans, 1969, 12, pp 301308.Google Scholar
13. Norris, L.H. and Reynolds, W.C. Turbulent channel flow with a moving wavy boundary, Report FM-10, Dept Mech Eng, Stanford University, 1975.Google Scholar
14. Launder, B.E. and Sharma, B.I. Application of the energy-dissipation model of turbulence to the calculation of flow near a spinning disc, Letters in Heat Mass Transf, 1974, 1, pp 131138.Google Scholar
15. Lien, F.S. and Leschziner, M.A. Modelling 2D separation from high-lift aerofoil with non-linear eddy-viscosity model and second-moment closure, Aeronaut J, April 1995, 99, (984), pp 125144.Google Scholar
16. Lien, F.S. and Leschziner, M.A. Computational modelling of a transitional 3D turbine-cascade flow using a modified low-Re k-ε model and a multi-block scheme, ASME Paper 95-CTP-80, 1995.Google Scholar
17. Lien, F.S. and Leschziner, M.A. A general non-orthogonal collocated FV algorithm for turbulent flow at all speeds incorporating secondmoment closure, Part 1: computational implementation and Part 2: applications, Comp Meth Appl Mech Eng, 1994, 114, pp 123148 and pp 149-167.Google Scholar
18. Lien, F.S. High performance computing of turbulent flows, ERCOFTAC Course on High Performance Computing in Fluid Dynamics, Wesseling, P. (ed), Kluwer Academic Publishers, 1996, pp 201236.Google Scholar
19. Lien, F.S. and Leschziner, M.A. Second-moment closure for threedimensional turbulent flow around and within complex geometries, Comps and Fluids, 1996, 25, pp 237262.Google Scholar
20. Lien, F.S. and Leschziner, M.A. Upstream monotonic interpolation for scalar transport with application in complex turbulent flows, Int J Num Meth Fluids, 1994, 19, pp 527548.Google Scholar
21. Craft, T.J., Launder, B.E. and Suga, K. Extending the applicability of eddy viscosity models through the use of deformation invariants and non-linear elements, Proc 5th Int Symp on Refined Flow Modelling and Turbulence Measurements, Paris, 1993, pp 125132.Google Scholar