Turbulent Shear Flows 8 pp 169-187 | Cite as

# Large-Eddy Simulation of a Turbulent Flow with Separation

## Abstract

Large-eddy simulations of the fully-developed, turbulent channel flow over a rearward-facing step are presented and discussed. Predicted mean-flow quantities of the high Reynolds number flow compare well with the results of experimental investigations of the same flow. A momentum balance including all the terms appearing in the Reynolds-averaged Navier-Stokes equations demonstrates the importance of the stress terms in the separation and reattachment regions of the flow. Spectra taken from time series of the fluctuating pressure reveal the presence of low-frequency motion in the recirculation zone. Similar behavior has been observed in experimental studies of separated flows occurring in a variety of geometries. Finally, the instantaneous flow field is analyzed for the presence of topological flow patterns typical for turbulent shear flows. To what extent such events contribute to the statistical properties of the flow is discussed.

## Keywords

Shear Layer Recirculation Zone Separation Bubble Separate Shear Layer Turbulent Shear Flow## Preview

Unable to display preview. Download preview PDF.

## References

- Adams, E.W. & Johnston, J.P (1988): “Effects of the separating shear layer on the reattachment flow structure, part 2: reattachment length and wall shear stress”, Exp. Raids, Vol. 6, pp. 493–499.Google Scholar
- Amal, M. and Friedrich, R. (1991a): “Investigation of the Pressure and Velocity Fields in a Turbulent Separated Flow Using the LES Technique”, AIAA Paper No. 91–0251, 29th Aerospace Sciences Meeting, Reno, USA, Jan. 7–10.Google Scholar
- Amal, M. & Friedrich, R. (1991b): “On the effects of spatial resolution and subgridscale modeling in the large eddy simulation of a recirculating flow”, to
*appear in*Proc. of th 9th GAMM-Conf. on Numerical Methods in Fluid Mechanics, (Vieweg Verlag, Braunschweig).Google Scholar - Chorin, A.J. (1968): “Numerical solution of the Navier-Stókes equations”, Math. of Comp., Vol. 22, pp. 745–762.MathSciNetMATHCrossRefGoogle Scholar
- Driver, D.M., Seegmiller, H.L. & Marvin, J.G. (1987): “Tune-dependent behavior of a reattaching shear layer”, AIAA Journal, Vol. 25, No. 7, pp. 914–919.ADSCrossRefGoogle Scholar
- Dianat, M. & Castro, I.P. (1991): “Turbulence in a separated boundary layer”, J. Fluid Mech., Vol. 226, pp. 91–123.ADSCrossRefGoogle Scholar
- Durst, F. & Schmitt, F. (1985): “Experimental study of high Reynolds number backward-facing step flow”, in Proc. 5th Symp. on Turbulent Shear Flows, Aug. 7.-9 (Cornell University, Ithaca, NY).Google Scholar
- Eaton, J.K. & Johnston, J.P. (1981): “Low frequency unsteadiness of a reattaching turbulent shear layer”; in Turbulent Shear Flows 3, ed. L.J.S. Bradbury, F. Durst, B.E. Launder, F.W. Schmitt & J.H. Whitelaw (Springer-Verlag, Berlin) pp. 162–170.Google Scholar
- Friedrich, R. (1988): “Simulation of turbulent flows”, in Computational Methods in Flow Analysis, ed. by H. Niki and M. Kawahara (Okayama University of Science, Japan), Vol. 2, pp. 833–843.Google Scholar
- Germano, M., Piomelli, U., Moin, P. & Cabot, W.H. (1991): “A dynamic subgridscale eddy viscosity model”, Phys. Fluids A, Vol. 3, No. 7, pp. 1760–1765.ADSMATHCrossRefGoogle Scholar
- Hunt, J.C.R., Wray, A.A. & Moin, P. (1988): “Eddies, streams and convergence zones in turbulent flows”, in Proc. of the Summer Program 1988, Report CTR-S88 (Center for Turbulence Research, Stanford, CA) pp. 193–208.Google Scholar
- Isomoto, K. & Honami, S. (1989): “The effect of inlet turbulence intensity on the reattachment process over a backward-facing step”, J. Fluids Eng., Vol. 111, pp. 87–92.CrossRefGoogle Scholar
- Kiya, M. & Sasaki, K. (1983): “Structure of a turbulent separation bubble”, J. Fluid Mech., Vol. 137, pp. 83–113.ADSCrossRefGoogle Scholar
- Klein, H. & Friedrich, R. (1990): “Large eddy simulation of manipulated boundary layer and channel flows”, in Turbulence Control by Passive Means, ed. by E. Coustols (Kluwer Academic Publishers, Dordrecht) pp. 41–65.Google Scholar
- McCluskey, F., Hancock, P.E. & Castro, I.P (1991): “Three–dimensional separated flows”, in Proc. 8th Symp. on Turbulent Shear Flows, Sept. 9–11 (Technical University of Munich, Germany) pp. 9–5–1–6.Google Scholar
- Moin, P., Squires, K., Cabot, W. & Lee, S. (1991): “A dynamic subgrid-scale model for compressible turbulence and scalar transport”, Phys. Fluids A, Vol. 3, No. 11, pp. 2746–2757.ADSMATHCrossRefGoogle Scholar
- Piomelli, U., Ferziger, J., Moin, P. & Kim, J. (1989): “ New approximate boundary conditions for large-eddy simulations of wall-bounded flow”, Phys. Fluids A, Vol. 1, No. 6, pp. 1061–1068.ADSCrossRefGoogle Scholar
- Richter, K., Friedrich, R. & Schmitt, L. (1987): “I arge-eddy simulation of turbulent wall boundary layers with pressure gradient”, in Proc. 6th Symp. on Turbulent Shear Flows (Paul Sabatier University, Toulouse) pp. 22.3.1–7.Google Scholar
- Roshko, A. & Lau, J.C. (1965): “Some observations on transition and reattachment of a free shear layer in incompressible flow”, in Proc. Heat Transfer and Fluid Mechanics Institute, ed. A.F. Charawat (Stanford University Press, Standord, CA) pp. 157–167.Google Scholar
- Sandham, N.D, & Kleiser, L. (1991): “Vortex formation in the late stages of transition to turbulence”, in Proc. of the Boundary Layer Transition and Control Conf., April 8–12 (Royal Aeronautical Society, Cambridge, UK) pp. 26.1–12.Google Scholar
- Schumann, U. (1975): “Subgrid scale model for finite difference simulations of turbulent flows in plane channels and annuli”, J. Comp. Phys., Vol. 18, pp. 376–404.MathSciNetADSMATHCrossRefGoogle Scholar
- Simpson, R.L., Chew, Y.-T. & Shivaprasad, B.G. (1981): “The structure of a separating turbulent boundary layer. part 2: Higher-order turbulence results”, J. Fluid Mech., Vol. 113, pp. 53–73.ADSCrossRefGoogle Scholar
- Su, M.D. & Friedrich, R. (1991): `Large eddy simulation of fully–developed turbulent flow in a straigth duct“, in Proc. 8th Symp. on Turbulent Shear Flows, Sept. 9–11 (Technical University of Munich, Germany) pp. II–19–1–2.Google Scholar
- Tafti, D.K. & Vanka, S.P. (1991a): “A numerical study of flow separation and reattachment on a blunt plate”, Phys. Fluids A, Vol. 3, No. 7, pp. 1749–1759.ADSMATHCrossRefGoogle Scholar
- Tafti, D.K. & Vanka, S.P. (1991b): “A three-dimensional numerical study of flow separation and reattachment on a blunt plate”, Phys. Fluids A, Vol. 3, No. 12, pp. 2887–2909.ADSMATHCrossRefGoogle Scholar
- Unger, F. & Friedrich, R. (1991): “Large eddy simulation of fully–developed turbulent pipe flow”, in Proc. 8th Symp. on Turbulent Shear Flows, Sept. 9.11 (Technical University of Munich, Germany) pp. 19–3–1–6.Google Scholar