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On the interaction of compliant coatings with boundary-layer flows

Published online by Cambridge University Press:  20 April 2006

Mohamed Gad-El-Hak ,
Ron F. Blackwelder  and
James J. Riley
Mohamed Gad-El-Hak
Affiliation:
Flow Research Company, 21414 68th Avenue South, Kent. Washington 98032
Ron F. Blackwelder
Affiliation:
Flow Research Company, 21414 68th Avenue South, Kent. Washington 98032 Permanent address: Department of Aerospace Engineering, University of Southern California, Los Angeles, CA 90007.
James J. Riley
Affiliation:
Flow Research Company, 21414 68th Avenue South, Kent. Washington 98032 Present address: Department of Mechanical Engineering, University of Washington, Seattle, WA 98105.
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Abstract

The interactions of compliant coatings with laminar, transitional and turbulent boundary layers are investigated. A 2 m long flat plate is towed in the range of speeds of 20–140 cm/s in an 18 m water channel using a carriage riding on an oil film. Isotropic and anistropic compliant coatings are used to cover about 20% of the working Plexiglas surface. The compliant material used is a viscoelastic plastisol gel produced by heating a mixture of polyvinyl chloride resin, a plasticizer and a stabilizer, and allowing them to gel. The shear modulus of rigidity of the plastisol was varied by changing the percentage of PVC in the mix. Anisotropy is introduced by placing the plastisol on a rubber surface having longitudinal grooves scaled with the low-speed streaks in the turbulent boundary layer. The most pronounced effect of the surface compliance in a turbulent boundary layer is a hydroelastic instability in the form of a spanwise wave structure on the compliant surface. The compliant-surface deformation was measured using a novel remote optical technique. The onset speed of the hydroelastic instability waves depends on the thickness and the modulus of rigidity of the plastisol. Their wavelength, wave speed and amplitude are found to depend on these plastisol parameters as well as on the towing speed. In a laminar boundary layer with freestream speeds of over twice the corresponding onset velocity for the turbulent case, no similar instability is observed.

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 140 , March 1984 , pp. 257 - 280
Copyright
© 1984 Cambridge University Press

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References

Benjamin, T. B. 1960 Effects of a flexible boundary on hydrodynamic stability. J. Fluid Mech. 9, 513.Google Scholar
Benjamin, T. B. 1963 The threefold classification of unstable disturbances in flexible surfaces bounding inviscid flows. J. Fluid Mech. 16, 436.Google Scholar
Benjamin, T. B. 1964 Fluid flow with flexible boundaries. In Proc. 11th Intl Congr. Appl. Mech., Munich (ed. H. Görtler), p. 109. Springer.
Betchov, K. 1960 Simplified analysis of boundary-layer oscillations. J. Ship Res. 4, 37.Google Scholar
Blackwelder, R. F. & Kaplan, R. E. 1976 On the wall structure of the turbulent boundary layer. J. Fluid Mech. 76, 89.Google Scholar
Boggs, F. W. & Hahn, E. R. 1962 Performance of compliant skins in contact with high velocity flow in water. In Proc. 7th Joint Army-Navy-Air Force Conf. on Elastomer Research and Development. San Francisco, vol. 2, p. 443. U.S. Office of Naval Research.
Bushnell, D. M., Hefner, J. N. & Ash, R. L. 1977 Effect of compliant wall motion on turbulent boundary layers. Phys. Fluids Suppl. 20, S31.Google Scholar
Clauser, F. H. 1956 The turbulent boundary layer. Adv. Appl. Mech. 4, 1.Google Scholar
Corino, E. R. & Brodkey, R. S. 1969 A visual investigation of the wall region in turbulent flow. J. Fluid Mech. 37, 1.Google Scholar
Duncan, J. H., Waxman, A. M. & Tulin, M. P. 1982 Dispersion relationships for waves at the interface between a single layer visco-elastic compliant coating and a turbulent flow. Hydronautics Tech. Rep. 8111–1.Google Scholar
Falco, R. E. 1977 Coherent motions in the outer region of turbulent boundary layers. Phys. Fluids Suppl. 20, S124.Google Scholar
Fischer, M. C. & Ash, R. L. 1974 A general review of concepts for reducing skin friction, including recommendations for future studies. NASA Tech. Memo. X-2894.Google Scholar
Fischer, M. C., Weinstein, L. M., Bushnell, D. M. & Ash, R. L. 1975 Compliant wall turbulent skin friction reduction reasearch. AIAA 8th Fluid and Plasma Dyn. Conf., Hartford, CT; Paper 75–833.Google Scholar
Gad-el-Hak, M., Blackwelder, R. F. & Riley, J. J. 1981 On the growth of turbulent regions in laminar boundary layers. J. Fluid Mech. 110, 73.Google Scholar
Gad-el-Hak, M., Blackwelder, R. F. & Riley, J. J. 1982 Interaction of compliant surfaces with transitional and turbulent boundary layers. In Proc. IUTAM Symp. on Structure of Complex Turbulent Shear Flow, Marseille (ed. R. DumasM & L. Fulachier), p. 20. Springer.
Hansen, R. J. & Hunston, D. L. 1974a An experimental study of turbulent flows over compliant surfaces. J. Sound Vib. 34, p. 297.Google Scholar
Hansen, R. J. & Hunston, D. L. 1974b An experimental study of the hydrodynamic drag on compliant surfaces: fluid property effects. In Proc. 8th Intl Cong. Acoust., vol. 2, p. 579. Inst. Sound & Vib. Res., Southampton University.
Hansen, R. J. & Hunston, D. L. 1976 Further observations on flow-generated surface waves in compliant surfaces. J. Sound Vib. 46, 593.Google Scholar
Hansen, R. J. & Hunston, D. L. 1983 Fluid-property effects on flow-generated waves on a compliant surface. J. Fluid Mech. 133, 161.Google Scholar
Hansen, R. J., Hunston, D. L., Ni, C. C. & Reischman, M. M. 1980a An experimental study of flow-generated waves on a flexible surface. J. Sound Vib. 68, 317.Google Scholar
Hansen, R. J., Hunston, D. L., Ni, C. C., Reischman, M. M. & Hoyt, J. W. 1980b Hydrodynamic drag and surface deformations generated by liquid flows over flexible surfaces. In Viscous Flow Drag Reduction (ed. G. R. Hough), p. 439. AIAA Prog. Astro. Aero., vol. 72.
Hoyt, J. W. 1981 A flow-visualization study of turbulent spots on solid and compliant surfaces. In Proc. 7th Symp. Turbulence, Rolla, Missouri (ed. J. L. Zakin & G. K. Patterson), p. 32–1.
Jaeger, J. C. & Cook, N. G. W. 1976 Fundamental of Rock Mechanics, 2nd edn, p. 314. Chapman & Hall.
Kaplan, R. E. 1964 The stability of laminar incompressible boundary layers in the presence of compliant boundaries. Sc.D. thesis, MIT.
Kline, S. J., Reynolds, W. C., Schraub, F. A. & Runstadler, P. W. 1967 The structure of turbulent boundary layers. J. Fluid Mech. 30, 741.Google Scholar
Kovasznay, L. S. G., Kibens, V. & Blackwelder, R. F. 1970 Large-scale motion in the intermittent region of a turbulent boundary layer. J. Fluid Mech. 41, 283.Google Scholar
Kramer, M. O. 1957 Boundary layer stabilization by distributed damping. J. Aero. Sci. 24, 283.Google Scholar
Kramer, M. O. 1962 Boundary layer stabilization by distributed damping. J. Am. Soc. Nav. Engrs 74, 341.Google Scholar
Landahl, M. T. 1962 On the stability of laminar incompressible boundary layer over a flexible surface. J. Fluid Mech. 13, 609.Google Scholar
Landau, L. D. & Liftshitz, E. M. 1970 The Theory of Elasticity. Pergamon.
Lissaman, P. B. S. & Harris, G. L. 1969 Turbulent skin friction on compliant surfaces. AIAA 7th Aerospace Sci. Meeting. New York; Paper 69–164.Google Scholar
Liu, H.-T., Katsaros, K. B. & Weissman, M. A. 1982 Dynamic response of thin-wire wave gauges. J. Geophys. Res. 87, 5686.Google Scholar
McMichael, J. M., Klebanoff, P. S. & Mease, N. E. 1980 Experimental investigation of drag on a compliant surface. In Viscous Flow Drag Reduction (ed. G. R. Hough), p. 410. AIAA Astro. Aero., vol. 72.
Orszag, S. H. 1979 Prediction of compliant wall drag reduction. NASA Contractor Rep. 3071.Google Scholar
Puryear, F. W. 1962 Boundary layer control - drag reduction by use of compliant coatings. David Taylor Model Basin Rep. 1668.Google Scholar
Rayleigh, F. 1887 On waves propagated along the plane surface of an elastic solid. Math. Soc. Proc. Lond. 17, 3.Google Scholar
Smith, R. L. & Blick, E. F. 1969 Skin friction of compliant surfaces with foamed material substrate. J. Hydronaut. 3, 100.Google Scholar
Walsh, M. J. 1980 Drag characteristics of V-groove and transverse curvature riblets. In Viscous Flow Drag Reduction (ed. G. R. Hough), p. 168. AIAA Prog. Astro. Aero., vol. 72.
Weaver, D. S. & Unny, T. E. 1970 The hydroelastic stability of a flat plate. Trans. ASME E: J. Appl. Mech. 37, 823.Google Scholar
Weaver, D. S. & Unny, T. E. 1973 On the dynamic stability of fluid-conveying pipes. Trans. ASME E: J. Applied Mech. 40, 48.Google Scholar
Willmarth, W. W. & Lu, S. S. 1972 Structure of the Reynolds stress near the wall. J. Fluid Mech. 55, 65.Google Scholar