Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-05T16:50:17.140Z Has data issue: false hasContentIssue false

Global linear and nonlinear stability of viscous confined plane wakes with co-flow

Published online by Cambridge University Press:  04 April 2011

OUTI TAMMISOLA*
Affiliation:
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
FREDRIK LUNDELL
Affiliation:
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden Wallenberg Wood Science Center, KTH Mechanics, SE-100 44 Stockholm, Sweden
PHILIPP SCHLATTER
Affiliation:
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
ARMIN WEHRFRITZ
Affiliation:
Linné FLOW Centre, KTH Mechanics, Royal Institute of Technology, SE-100 44 Stockholm, Sweden
L. DANIEL SÖDERBERG
Affiliation:
Wallenberg Wood Science Center, KTH Mechanics, SE-100 44 Stockholm, Sweden Innventia AB, Box 5604, SE-114 86 Stockholm, Sweden
*
Email address for correspondence: [email protected]

Abstract

The global stability of confined uniform density wakes is studied numerically, using two-dimensional linear global modes and nonlinear direct numerical simulations. The wake inflow velocity is varied between different amounts of co-flow (base bleed). In accordance with previous studies, we find that the frequencies of both the most unstable linear and the saturated nonlinear global mode increase with confinement. For wake Reynolds number Re = 100 we find the confinement to be stabilising, decreasing the growth rate of the linear and the saturation amplitude of the nonlinear modes. The dampening effect is connected to the streamwise development of the base flow, and decreases for more parallel flows at higher Re. The linear analysis reveals that the critical wake velocities are almost identical for unconfined and confined wakes at Re ≈ 400. Further, the results are compared with literature data for an inviscid parallel wake. The confined wake is found to be more stable than its inviscid counterpart, whereas the unconfined wake is more unstable than the inviscid wake. The main reason for both is the base flow development. A detailed comparison of the linear and nonlinear results reveals that the most unstable linear global mode gives in all cases an excellent prediction of the initial nonlinear behaviour and therefore the stability boundary. However, the nonlinear saturated state is different, mainly for higher Re. For Re = 100, the saturated frequency differs less than 5% from the linear frequency, and trends regarding confinement observed in the linear analysis are confirmed.

Type
Papers
Copyright
Copyright © Cambridge University Press 2011

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Present address: Aalto University, Faculty of Engineering and Architecture, Department of Energy Technology, PO Box 14300, FI-00076 Aalto, Finland

References

REFERENCES

Berkooz, G., Holmes, P. & Lumley, J. L. 1993 The proper orthogonal decomposition in the analysis of turbulent flows. Annu. Rev. Fluid Mech. 25, 539575.CrossRefGoogle Scholar
Biancofiore, L., Gallaire, F. & Pasquetti, R. 2011 Influence of confinement on a two-dimensional wake. J. Fluid Mech. (submitted).CrossRefGoogle Scholar
Briggs, R. J. 1964 Electron–Stream Interaction with Plasmas. MIT.CrossRefGoogle Scholar
Camarri, S. & Giannetti, F. 2007 On the inversion of the von Kármán street in the wake of a confined square cylinder. J. Fluid Mech. 574, 169178.CrossRefGoogle Scholar
Chomaz, J.-M. 2005 Global instabilities in spatially developing flows: non-normality and nonlinearity. Annu. Rev. Fluid Mech. 37, 357392.CrossRefGoogle Scholar
Davis, R. W., Moore, E. F. & Purtell, L. P. 1984 A numerical–experimental study of confined flow around rectangular cylinders. Phys. Fluids 27, 4659.CrossRefGoogle Scholar
Drazin, P. G. & Reid, W. H. 1981 Hydrodynamic Stability, 9th edn. Cambridge University Press.Google Scholar
Ehrenstein, U. & Gallaire, F. 2005 On two-dimensional temporal global modes in spatially evolving open flows: the flat-plate boundary layer. J. Fluid Mech. 536, 209218.CrossRefGoogle Scholar
Fischer, P. F. 1997 An overlapping Schwarz method for spectral element solution of the incompressible Navier–Stokes equations. J. Comput. Phys. 133, 84101.CrossRefGoogle Scholar
Hammond, D. A. & Redekopp, L. G. 1997 Global dynamics of symmetric and asymmetric wakes. J. Fluid Mech. 331, 231260.CrossRefGoogle Scholar
Huerre, P. & Monkewitz, P. A. 1990 Local and global instabilities in spatially developing flows. Annu. Rev. Fluid Mech. 22, 473537.CrossRefGoogle Scholar
Juniper, M. P. 2006 The effect of confinement on the stability of two-dimensional shear flows. J. Fluid Mech. 565, 171195.CrossRefGoogle Scholar
Lehoucq, R. B., Sorensen, D. C. & Yang, C. 1998 ARPACK Users' Guide: Solution of Large-Scale Eigenvalue Problems with Implicitly Restarted Arnoldi Methods. SIAM.CrossRefGoogle Scholar
Maday, Y. & Patera, A. T. 1989 Spectral element methods for the Navier–Stokes equations. In State-of-the-Art Surveys on Computational Mechanics (ed. Noor, A.), pp. 71143. ASME.Google Scholar
Maschhoff, K. J. & Sorensen, D. 1996 P_ARPACK: an efficient portable large scale eigenvalue package for distributed memory parallel architectures. In Applied Parallel Computing: Industrial Computation and Optimization (ed. Wasniewski, J.), pp. 478486. Springer.CrossRefGoogle Scholar
Pier, B., Huerre, P. & Chomaz, J.-M. 2001 Bifurcation to fully nonlinear synchronized structures in slowly varying media. Physica D 148, 4996.CrossRefGoogle Scholar
Rees, S. J. & Juniper, M. P. 2010 The effect of confinement on the stability of viscous planar jets and wakes. J. Fluid Mech. 656, 309336.CrossRefGoogle Scholar
Richter, A. & Naudascher, E. 1976 Fluctuating forces on a rigid circular cylinder in confined flow. J. Fluid Mech. 78, 561576.CrossRefGoogle Scholar
Rodriguez, D. & Theofilis, V. 2009 Massively parallel solution of the biglobal eigenvalue problem using dense linear algebra. AIAA J. 47 (10), 24492459.CrossRefGoogle Scholar
Rowley, C. W., Colonius, T. & Basu, A. J. 2002 On self-sustained oscillations in two-dimensional compressible flow over rectangular cavities. J. Fluid Mech. 455, 315346.CrossRefGoogle Scholar
Rowley, C. W., Mezic, I., Bagheri, S., Schlatter, P. & Henningson, D. S. 2009 Spectral analysis of nonlinear flows. J. Fluid Mech. 641, 115127.CrossRefGoogle Scholar
Schmid, P. J. & Henningson, D. S. 2001 Stability and Transition in Shear Flows. Springer.CrossRefGoogle Scholar
Shaw, T. L. 1971 Effect of side walls on flow past bluff bodies. J. Hydraul. Div. 97, 6579.CrossRefGoogle Scholar
Sipp, D. & Lebedev, A. 2007 Global stability of base and mean flows: a general approach and its applications to cylinder and open cavity flows. J. Fluid Mech. 593, 333358.CrossRefGoogle Scholar
Suzuki, H., Inoue, Y., Nishimura, T., Fukutani, K. & Suzuki, K. 1994 Unsteady flow in a channel obstructed by a square rod (crisscross motion of vortex). Intl J. Heat Fluid Flow 14, 29.CrossRefGoogle Scholar
Tammisola, O. 2009 Linear stability of plane wakes and liquid jets: global and local approach. Licentiate thesis, Royal Institute of Technology, Stockholm, Sweden.Google Scholar
Theofilis, V. 2003 Advances in global linear instability analysis of nonparallel and three-dimensional flows. Prog. Aerosp. Sci. 39, 249315.CrossRefGoogle Scholar
Weideman, J. A. C. & Reddy, S. C. 2000 A MATLAB differentiation matrix suite. Trans. Math. Softw. 26 (4), 465519.CrossRefGoogle Scholar
Yu, M.-H. & Monkewitz, P. A. 1990 The effect of nonuniform density on the absolute instability of two-dimensional inertial jets and wakes. Phys. Fluids A 2, 11751181.CrossRefGoogle Scholar