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Dynamics and stability of a vortex ring impacting a solid boundary

Published online by Cambridge University Press:  26 April 2006

J. D. Swearingen
Affiliation:
Naval Research Laboratory, Washington, DC 20375, USA Present address: Mechanical Engineering Department, The University of Kansas, Lawrence, KS 66045, USA
J. D. Crouch
Affiliation:
Naval Research Laboratory, Washington, DC 20375, USA Present address: Boeing Commercial Airplane Group, PO Box 3707, MS 7H-90, Seattle, WA 98124-2207, USA
R. A. Handler
Affiliation:
Naval Research Laboratory, Washington, DC 20375, USA

Abstract

Direct numerical simulations were used to study the dynamics of a vortex ring impacting a wall at normal incidence. The boundary layer formed as the ring approaches the wall undergoes separation and roll-up to form a secondary vortex ring. The secondary ring can develop azimuthal instabilities which grow rapidly owing to vortex stretching and tilting in the presence of the mean strain field generated by the primary vortex ring. The stability of the secondary ring was investigated through complementary numerical experiments and stability analysis. Both perturbed and unperturbed evolutions of the secondary ring were simulated at a Reynolds number of about 645, based on the initial primary-ring propagation velocity and ring diameter. The linear evolution of the secondary vortex-ring instability was modelled analytically by making use of a quasi-steady approximation. This allowed a localized stability analysis following Widnall & Sullivan's (1973) earlier treatment of an isolated vortex ring. Amplitude evolution and growth-rate predictions from this analysis are in good agreement with the simulation results. The analysis shows that the secondary vortex ring is unstable to long-wavelength perturbations, even though an isolated ring having similar characteristics would be stable.

Type
Research Article
Copyright
© 1995 Cambridge University Press

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References

Acalar, M. S. & Smith, C. R. 1987 A study of hairpin vortices in a laminar boundary layer. Part 2. Hairpin vortices generated by fluid injection. J. Fluid Mech. 175, 4383.Google Scholar
Bernal, L. P. & Kwon, J. T. 1989 Vortex ring dynamics at a free surface. Phys. Fluids A 1, 449451.Google Scholar
Bernard, P. S., Thomas, J. T. & Handler, R. A. 1993 Vortex dynamics and the production of Reynolds stress. J. Fluid Mech. 253, 385419.Google Scholar
Brooke, J. W. & Hanratty, T. J. 1993 Origin of turbulence-producing eddies in a channel flow. Phys. Fluids A 5, 10111022.Google Scholar
Cantwell, B. J. 1986 Viscous starting jets. J. Fluid Mech. 173, 159189.Google Scholar
Cerra, A. W. & Smith, C. R. 1983 Experimental observations of vortex ring interaction with the fluid adjacent to a surface. Rep. FM-4. Department of Mechanical Engineering and Mechanics, Leigh University, Bethlehem, PA.
Chu, C. C. & Falco, R. E. 1988 Vortex ring/viscous wall layer interaction model of the turbulence production process near walls. Exps. Fluids 6, 305315.Google Scholar
Doligalski, T. L., Smith, C. R. & Walker, J. D. A. 1994 Vortex interaction with walls. Ann. Rev. Fluid Mech. 26, 573616.Google Scholar
Dommermuth, D. G. 1993 The laminar interaction of a pair of vortex tubes with a free surface. J. Fluid Mech. 246, 91115.Google Scholar
Falco, R. E. 1991 A coherent structure model of the turbulent boundary layer and its ability to predict Reynolds number dependence. Phil. Trans. R. Soc. Lond. A 336, 103129.Google Scholar
Goldstein, D., Handler, R. & Sirovich, L. 1993 Modeling a no-slip flow boundary with an external force field. J. Comput. Phys. 105, 354366.Google Scholar
Gottleib, D. & Orszag, S. A. 1977 Numerical Analysis of Spectral Methods: Theory and Applications. CBMS-NSF, Society for Industrial and Applied Mathematics. Philadelphia, PA, USA.
Herbert, Th. 1983 Secondary instability of plane channel flow to subharmonic three-dimensional disturbances. Phys. Fluids 26, 871874.Google Scholar
Kim, J., Moin, P. & Moser, R. 1987 Turbulence statistics in fully developed channel flow at low Reynolds number. J. Fluid Mech. 177, 133166.Google Scholar
Lim, T. T. 1989 An experimental study of a vortex ring interacting with an inclined wall. Exps. Fluids 7, 453463.Google Scholar
Magarvey, R. H. & Maclatchy, C. S. 1964a The formation and structure of vortex rings. Can. J. Phys. 42, 678683.Google Scholar
Magarvey, R. H. & Maclatchy, C. S. 1964b The disintegration of vortex rings. Can. J. Phys. 42, 684689.Google Scholar
Maxworthy, T. 1972 The structure and stability of vortex rings. J. Fluid Mech. 51, 1532.Google Scholar
Mccormack, P. D. & Crane, L. 1973 Physical Fluid Dynamics. Academic.
Moore, D. W. & Saffman, P. G. 1974 A note on the stability of a vortex ring of small cross-section. Proc. R. Soc. Lond. A 338, 535537.Google Scholar
Orlandi, P. 1990 Vortex dipole rebound from a wall. Phys. Fluids A 2, 14291436.Google Scholar
Orlandi, P. & Verzicco, R. 1993 Vortex rings interacting with walls: axisymmetric and three-dimensional simulations. J. Fluid Mech. 256, 615646.Google Scholar
Orszag, S. A. & Patera, A. T. 1981 Subcritical transition to turbulence in planar shear flows. In Transition and Turbulence (ed. R. E. Meyer), pp. 127146. Academic.
Orszag, S. A. & Patera, A. T. 1983 Secondary instability of wall-bounded shear flows. J. Fluid Mech. 128, 347385.Google Scholar
Robinson, S. K. 1989 A review of vortex structures and associated coherent motions in turbulent boundary layers. In Proc. Second IUTAM Symp. on Structure of Turbulence and Drag Reduction. Zurich.
Robinson, S. K. 1991 Coherent motions in the turbulent boundary layer. Ann. Rev. Fluid Mech. 23, 601639.Google Scholar
Saffman, P. G. 1975 On the formation of vortex rings. Stud. Appl. Maths. 54, 261268.Google Scholar
Saffman, P. G. 1978 The number of waves on unstable vortex rings. J. Fluid Mech. 84, 625639.Google Scholar
Sallet, D. W. & Widmayer, R. S. 1974 An experimental investigation of laminar and turbulent vortex rings in air. Z. Flugwiss. 22, 207215.Google Scholar
Sarpkaya, T. & Suthon, P. B. 1991 Scarred and striated signature of a vortex pair on the free surface. In Proc. Eighteenth Symp. on Naval Hydrodyn., University of Michigan, 19-24 August 1990, pp. 503518. National Academy.
Smith, C. R., Walker, J. D. A., Haidari, A. H. & Sobrun, U. 1991 On the dynamics of near-wall turbulence, Phil. Trans. R. Soc. Lond. A 336, 134175.Google Scholar
Swearingen, J. D., Crouch, J. D. & Handler, R. A. 1991 Stability aspects of vortex ring/wall interaction. Bull. Am. Phys. Soc. 36, 2661.Google Scholar
Walker, J. D. A., Smith, C. R., Cerra, A. W. & Doligalski, T. L. 1987 The impact of a vortex ring on a wall. J. Fluid Mech. 181, 99140.Google Scholar
Widnall, S. E., Bliss, D. B. & Tsai, C. Y. 1974 The instability of short waves on a vortex ring. J. Fluid Mech. 66, 3547.Google Scholar
Widnall, S. E. & Sullivan, J. P. 1973 On the stability of vortex rings. Proc. R. Soc. Lond. A 332, 335353.Google Scholar
Willmarth, W. W., Tryggvason, G., Hirsa, A. & Yu, D. 1989 Vortex pair generation and interaction with a free surface. Phys. Fluids A 1, 170172.Google Scholar
Yamada, H. & Matsui, T. 1982 Visualization of vortex interaction using smoke-wire technique. In Flow Visualization II (ed. W. Merzkirch), pp. 355359. Hemisphere.