Hostname: page-component-cd9895bd7-gvvz8 Total loading time: 0 Render date: 2024-12-17T09:10:09.589Z Has data issue: false hasContentIssue false

The effect of anisotropic wall compliance on boundary-layer stability and transition

Published online by Cambridge University Press:  26 April 2006

Peter W. Carpenter
Affiliation:
School of Engineering, University of Exeter, Exeter. EX4 4QF. UK
Philip J. Morris
Affiliation:
School of Engineering, University of Exeter, Exeter. EX4 4QF. UK

Abstract

A fairly simple theoretical model of an anisotropic compliant wall has been developed. It has been used to undertake a comprehensive numerical study of boundary-layer stability over such walls. The study is based on linearized theory, makes the usual quasi-parallel-flow approximation, uses the Blasius profile as the basic undisturbed flow and assumes two-dimensional disturbances. An investigation is carried out of the effects of anisotropic wall compliance on the Tollmien–Schlichting waves and the two previously identified wall modes, namely travelling-wave flutter and divergence. In addition global convergence techniques are used to search for other possible instabilities.

An asymptotic theory, valid for high Reynolds numbers, is also presented. This can provide accurate estimates of the eigenvalues. It is applicable to a much wider class of compliant walls than the relatively simple model used for the numerical study. An important use of the asymptotic theory is to help identify and elucidate the various energy-exchange mechanisms responsible for stabilization or destabilization of the instabilities. A reduction in the production of disturbance energy by the Reynolds shear stress is the main reason for the favourable effect of anisotropic wall compliance on instability growth. Other energy-exchange mechanisms, which have been found to make a significant contribution, include energy transfer from the disturbance to the mean flow due to the interaction of the fluctuating shear stress and the displaced mean flow, and the work done by the perturbations in wall pressure and shear stress.

It is found that anisotropic wall compliance confers very considerable advantage with respect to reduction in instability growth rate and transition delay. Using a fairly conservative criterion an almost ten-fold rise in transitional Reynolds number is predicted for anisotropic walls having the appropriate properties. Anisotropic wall compliance makes travelling-wave flutter much more sensitive to viscous effects and has a considerable stabilizing influence. The application of global convergence methods has led to the discovery of an anomalous spatially growing eigenmode which, according to conventional interpretation, would represent an instability. Further study of an appropriate initial-value problem has revealed that the new eigenmode is probably not an instability and that, for compliant walls, complex wavenumbers with positive real and negative imaginary parts do not necessarily correspond to an instability.

Type
Research Article
Copyright
© 1990 Cambridge University Press

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.)

References

Babenko, V. V. & Surkina, P. M., 1969 Some hydrodynamic features of dolphin swimming. Bionika 3, 1926 (in Russian).Google Scholar
Bellman, R. E. & Kalaba, R. E., 1965 Quasilinearization and Boundary-Value Problems. American Elsevier.
Benjamin, T. B.: 1959 Shearing flow over a wavy boundary. J. Fluid Mech. 6, 161205.Google Scholar
Benjamin, T. B.: 1960 Effects of a flexible boundary on hydrodynamic stability. J. Fluid Mech. 9, 513532.Google Scholar
Benjamin, T. B.: 1963 The threefold classification of unstable disturbances in flexible surfaces bounding inviscid flows. J. Fluid Mech. 16, 436450.Google Scholar
Bridges, T. J. & Morris, P. J., 1984 Differential eigenvalue problems in which the parameter appears nonlinearly. J. Comput. Phys. 55, 437460.Google Scholar
Briggs, R. J.: 1964 Electron-Stream Interaction with Plasmas. MIT Press.
Carpenter, P. W.: 1984a The effect of a boundary layer on the hydroelastic instability of infinitely long plates. J. Sound Vib. 93, 461464.Google Scholar
Carpenter, P. W.: 1984b A note on the hydroelastic instability of orthotropic panels. J. Sound Vib. 94, 553554.Google Scholar
Carpenter, P. W.: 1984c The hydrodynamic stability of flow over non-isotropic compliant surfaces. Bull. Am. Phys. Soc. 29, 1534.Google Scholar
Carpenter, P. W.: 1985a Hydrodynamic and hydroelastic stability of flows over non-isotropic compliant surfaces. Bull. Am. Phys. Soc. 30, 1708.Google Scholar
Carpenter, P. W.: 1985b The optimization of compliant surfaces for transition delay. University of Exeter. School of Engineering, Tech. Note 85/2.Google Scholar
Carpenter, P. W.: 1987a The optimization of compliant surfaces for transition delay. In Proc. IUTAM Conf. on Turbulence Management & Relaminarisation. Bangalore. India (ed. H. W. Liepmann & R. Narasimha), pp. 305313. Springer.
Carpenter, P. W.: 1987b The hydrodynamic stability of flows over simple non-isotropic compliant surfaces. In Proc. Intl Conf. on Fluid Mech., Beijing, China, pp. 196201. Peking University Press.
Carpenter, P. W.: 1990 Status of transition delay using compliant walls. In Viscous Drag Reduction in Boundary Layers (ed. D. M. Bushnell & J. N. Heffner). pp. 79113. AIAA.
Carpenter, P. W. & Gajjar, J. S. B. 1990 A general theory for two- and three-dimensional wall-mode instabilities in boundary layers over isotropic and anisotropic compliant walls. Theor. Comput. Fluid Dyn. 2.Google Scholar
Carpenter, P. W. & Garrad, A. D., 1985 The hydrodynamic stability of flows over Kramer-type compliant surfaces. Part 1. Tollmien–Schlichting instabilities. J. Fluid Mech. 155, 465510.Google Scholar
Carpenter, P. W. & Garrad, A. D., 1986 The hydrodynamic stability of flows over Kramer-type compliant surfaces. Part 2. Flow-induced surface instabilities. J. Fluid Mech. 170, 199232.Google Scholar
Carpenter, P. W., Gaster, M. & Willis, G. J. K. 1983 A numerical investigation into boundary layer stability on compliant surfaces. In Numerical Methods in Laminar and Turbulent Flow, pp. 166172. Pineridge.
Carpenter, P. W. & Morris, P. J., 1985 The hydrodynamic stability of flows over non-isotropic compliant surfaces. Numerical solution of the differential eigenvalue problem. In Numerical Methods in Laminar and Turbulent Flow, pp. 16131620. Pineridge.
Carpenter, P. W. & Morris, P. J., 1989 Growth of three-dimensional instabilities in flow over compliant walls. Proc. 4th Asian Cong. of Fluid Mech., Hong Kong, pp. A206–209.Google Scholar
Daniel, A. P., Gaster, M. & Willis, G. J. K., 1987 Boundary layer stability on compliant surfaces. British Maritime Technology Ltd., Teddington, UK, Final Rep. 35020.Google Scholar
Dennis, J. E., Traub, J. F. & Weber, R. P., 1978 Algorithms for solvents of matrix polynomials. SIAM J. Numer. Anal. 15, 523533.Google Scholar
Domaradzki, J. A. & Metcalfe, R. W., 1987 Stabilization of laminar boundary layers by compliant membranes. Phys. Fluids 30, 695705.Google Scholar
Duncan, J. H.: 1988 The dynamic of waves at the interface between a two-layer viscoelastic coating and a fluid flow. J. Fluids Structures 2, 3551.Google Scholar
Duncan, J. H., Waxman, A. M. & Tulin, M. P., 1985 The dynamics of waves between a viscoelastic coating and a fluid flow. J. Fluid Mech. 158, 177197.Google Scholar
Williams, J. E. Ffowcs 1964 Reynolds stress near a flexible surface responding to unsteady air flow. Bolt, Berenek and Newman Inc., Cambridge, Mass., Rep. 1138.
Fraser, L. A. & Carpenter, P. W., 1985 A numerical investigation of hydroelastic and hydrodynamic instabilities in laminar flows over compliant surfaces comprising one or two layers of visco-elastic material. In Numerical methods in Laminar and Turbulent Flow, pp. 11711181. Pineridge.
Garrad, A. D. & Carpenter, P. W., 1982 A theoretical investigation of flow-induced instabilities in compliant coatings. J. Sound Vib. 85, 483500.Google Scholar
Gaster, M.: 1965 On the generation of spatially growing waves in a boundary layer. J. Fluid Mech. 22, 433441.Google Scholar
Gaster, M.: 1987 Is the dolphin a red herring? In Proc. IUTAM Conf. on Turbulence Management & Relaminarisation, Bangalore, India (ed. H. W. Liepmann & R. Narisimha), pp. 285304. Springer.
Grosskreutz, R.: 1971 Wechselwirkungen zwischen turbulenten Grenzschichten und weichen Wänden. MPI für Strömungsforschung und der AVA, Göttingen, Mitt. No. 53.Google Scholar
Ghosskreutz, R.: 1975 An attempt to control boundary-layer turbulence with nonisotropic compliant walls. University Sci. J. (Dar es Salaam) 1, 6773.Google Scholar
Jaffe, N. A., Okamura, T. T. & Smith, A. M. O. 1970 Determination of spatial amplification factors and their application to predicting transition. AIAA J. 8, 301308.Google Scholar
Jordinson, R.: 1970 The flat plate boundary layer. Part 1. Numerical integration of the Orr–Sommerfeld equation. J. Fluid Mech. 43, 801811.Google Scholar
Joslin, R. D.: 1987 The sensitivity of boundary layer instability growth rates to compliant wall properties. M. S. thesis, Pennsylvania State University.
Joslin, R. D. & Morris, P. J., 1989 The sensitivity of flow and surface properties to changes in compliant wall properties. J. Fluids Structures 3, 423432.Google Scholar
Joslin, R. D., Morris, P. W. & Carpenter, P. W., 1990 The role of three-dimensional instabilities in compliant-wall boundary-layer transition. AIAA Paper 90–0115.Google Scholar
Kramer, M. O.: 1960 Boundary layer stabilization by distributed damping. J. Am. Soc. Naval Engrs 72, 2533; J. Aero/Space Sci. 27, 69.Google Scholar
Landahl, M. T.: 1962 On the stability of a laminar incompressible boundary layer over a flexible surface. J. Fluid Mech. 13, 609632.Google Scholar
Lucey, A. D.: 1989 Hydroelastic instability of flexible surfaces. Ph.D. thesis, University of Exeter.
Lucey, A. D., Harris, J. B. & Carpenter, P. W., 1989 Three-dimensional hydroelastic instabilities of finite compliant panels. Proc. 4th Asian Cong. of Fluid Mech., Hong Kong, pp. 113.Google Scholar
Miles, J. W.: 1957 On the generation of surface waves by shear flows. J. Fluid Mech. 3, 185199.Google Scholar
Miles, J. W.: 1959a On the generation of surface waves. Part 2. J. Fluid Mech. 6, 568582.Google Scholar
Miles, J. W.: 1959b On the generation of surface waves. Part 3. Kelvin–Helmholtz instability. J. Fluid Mech. 6, 583598.Google Scholar
Miles, J. W.: 1962 On the generation of surface waves by shear flows. Part 4. J. Fluid Mech. 13, 433448.Google Scholar
Morris, P. J.: 1976 The spatial viscous instability of axisymmetric jets. J. Fluid Mech. 77, 511529.Google Scholar
Morris, P. J.: 1986 Applications of matrix factorization in hydrodynamic stability. In Trans. Fourth Army Conf. on Applied Maths and Computing, pp. 5366.Google Scholar
Prandtl, L.: 1921 Bermerkungen über die Enstehung der Turbulenz. Z. Angew. Math. Mech. 1, 431436.Google Scholar
Sen, P. K. & Arora, D. S., 1988 On the stability of laminar boundary-layer flow over a flat plate with a compliant surface. J. Fluid Mech. 197, 201240.Google Scholar
Smith, A. M. O. & Gamberoni, H. 1956 Transition, pressure gradient and stability theory. Douglas Aircraft Co., Long Beach, Calif. Rep. ES26388.Google Scholar
Stuart, J. T.: 1958 On the non-linear mechanisms of hydrodynamic stability. J. Fluid Mech. 4, 121.Google Scholar
Willis, G. J. K.: 1986 Hydrodynamic stability of boundary layers over compliant surfaces. Ph.D. thesis, University of Exeter.
Yeo, K. S.: 1986 The stability of flow over flexible surfaces. Ph.D. thesis. University of Cambridge.
Yeo, K. S.: 1988 The stability of boundary-layer flow over single- and multi-layer viscoelastic walls. J. Fluid Mech. 196, pp. 359408.Google Scholar
Yeo, K. S.: 1990 The hydrodynamic stability of boundary-layer flow over a class of anisotropic compliant walls. J. Fluid Mech. (in press).Google Scholar
Yeo, K. S. & Dowling, A. P., 1987 The stability of inviscid flows over passive compliant walls. J. Fluid Mech. 183, 265292.Google Scholar