Hostname: page-component-848d4c4894-pftt2 Total loading time: 0 Render date: 2024-05-16T02:30:36.346Z Has data issue: false hasContentIssue false

Dynamical aspects of vortex reconnection of perturbed anti-parallel vortex tubes

Published online by Cambridge University Press:  26 April 2006

M. J. Shelley
Affiliation:
Computational and Applied Mathematics Program, Department of Mathematics, University of Chicago, Chicago, IL 60637, USA
D. I. Meiron
Affiliation:
Applied Mathematics, California Institute of Technology, Pasadena, CA 91125, USA
S. A. Orszag
Affiliation:
Program in Applied and Computational Mathematics, Princeton University, Princeton, NJ 08544, USA

Abstract

The phenomenon of vortex reconnection is analysed numerically and the results are compared qualitatively with the predictions of a model of reconnection recently proposed by Saffman. Using spectral methods over both uniform and strained meshes, numerical simulations are performed of two nearly parallel, counter-rotating vortex tubes, over the range of Reynolds numbers Re = 1000–3500. The calculations utilizing a uniform mesh are performed for Re ≤ 1500 with a resolution of 128 points in each direction. The calculations utilizing a stretched mesh are performed for 1500 < Re ≤ 3500 with a resolution of up to 160 points in each direction and with a fourfold stretching about the region of reconnection. We present results for the variation of the maximum of vorticity, the time to reconnection, and other diagnostics of this flow as functions of the Reynolds number. From numerical simulation of the model equations, we infer and demonstrate the existence of exact solutions to the model to which its solutions arising from more general initial conditions are attracted at late times. In the limit of infinite Reynolds number, the model predicts eventual saturation of the axial strain, a feature observed in the recent work of Pumir & Siggia and also observed in our full numerical simulations. In this respect the model captures the observed local dynamics of vortex stretching. However, because the global effects of external flows are not included in the model, the model predicts that the axial strain eventually decays and the maximum vorticity grows linearly at late times. In contrast, from the full simulations, we see the possible emergence of the behaviour of the axial strain at infinite Reynolds number. As our simulations are affected by non-local effects, we do observe saturation of the strain but no subsequent decay. It is also shown analytically that the model predicts a reconnection time which varies logarithmically with increasing Reynolds number. Comparison with the full numerical simulations shows a much slower variation of the reconnection time with increasing Reynolds number than predicted by the model. Other points of agreement and disagreement between the Saffman model and the simulations are discussed, Reconnection is also discussed from the point of view of its relation to the possible onset of nearly singular behaviour of the Euler equation. In agreement with the recent numerical results of Pumir & Siggia, our results suggest that no singularity in the vorticity will form in a finite time for this initial condition.

Type
Research Article
Copyright
© 1993 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

Anderson, C. & Greengard, C. 1989 The vortex ring merger problem at infinite Reynolds number. Commun. Pure Appl. Maths 42, 1123.Google Scholar
Ashurst, W. T., Kerstein, A. R., Kerr, R. M. & Gibson, C. H. 1987 Alignment of vorticity and scalar gradient with strain rate in simulated Navier–Stokes turbulence. Phys. Fluids 30, 2343.Google Scholar
Ashurst, W. T. & Meiron, D. I. 1987 Numerical study of vortex reconnection. Phys Rev. Lett 58, 1632.Google Scholar
Batchelor, G. K. 1967 An Introduction to Fluid Dynamics. Cambridge University Press, Beale, J. T., Kato, T. & Majda, A. 1984 Remarks on the breakdown of smooth solutions for the 3-D Euler equations. Commun. Math. Phys. 94, 61.Google Scholar
Boratav, O. N., Pelz, R. B. & Zabusky, X. J. 1992 Reconnection in orthogonally interacting vortex tubes: Direct numerical simulations and quantifications. Phys. Fluids A 4, 581.Google Scholar
Brachet, M., Meiron, D., Nickel, B., Orszag, S. A. & Frisch, U. 1983 The small-scale structure of the Taylor-Green vortex. J. Fluid Mech. 130, 411.Google Scholar
Buntine, J. & Pullin, D. I. 1989 Merger and cancellation of strained vortices J. Fluid Mech. 205 1632.Google Scholar
Canuto, C., Hussaini, M. Y., Quarteroni, A. & Zang, T. A. 1988 Spectral Methods in Fluid Dynamics. Springer.
Chorin, A. 1982 Evolution of a turbulent vortex. Commun. Math. Phys. 83, 517.Google Scholar
Crow, S. 1970 Stability theory for a pair of trailing vortices. AIAA J. 8 2172.Google Scholar
Fohl, T. & Turner, J. S. 1975 Colliding vortex rings. Phys. Fluids 18, 433.Google Scholar
Gottlieb, D. & Orszag, S. A. 1971 Numerical Analysis of Spectral Methods: Theory and Applications. SIAM-CBMS.
Grauer, R. & Sideris, T. 1991 Numerical computation of 3d incompressible fluids with swirl. Phys. Rev. Lett. 67, 3511.Google Scholar
Kambe, T. 1983 A class of exact solutions of two-dimensional viscous flow. J. Phys. Soc. Japan 52, 834.Google Scholar
Kerr, R. M. & Hussain, A. K. M. F. 1989 Simulation of vortex reconnection. Physica D 37, 474.Google Scholar
Kida, S. 1987 Reconnection of vortex tubes. Proc. IUTAM Symp. on Fundamental Aspects of Vortex Motion, Tokyo (ed. H. Hasimoto & T. Kambe). North-Holland.
Kida, S. & Takaoka, M. 1991 Breakdown of frozen motion fields and vorticity reconnection. J. Phys. Soc. Japan 60, 2184.Google Scholar
Lundgren, T. S. & Ashurst, W. T. 1988 Area varying waves on curved vortex tubes with application to vortex breakdown. J. Fluid Mech. 200, 283.Google Scholar
Meiron, D., Shelley, M., Ashurst, W. T. & Orszag, S. A. 1989 Numerical studies of vortex reconnection. In Mathematical Aspects of Vortex Dynamics (ed. R. Caflisch). SIAM.
Melander, M. V. & Hussain, F. 1988 Cut-and-connect of two antiparallel vortex tubes. CTR Rep. CTR-588, p. 257.Google Scholar
Melander, M. V. & Hussain, F. 1989 Cross-linking of two antiparallel vortex tubes. Phys. Fluids A 1, 633.Google Scholar
Melander, M. V., McWilliams, J. C. & Zabusky, N. J. 1987 Axisymmetrization and vorticity gradient intensification of an isolated two-dimensional vortex through filamentation. J. Fluid Mech. 178, 137.Google Scholar
Melander, M. V. & Zabusky, N. 1987 Interaction and reconnection of vortex tubes via direct numerical simulations. In Proc. JUT AM Symp. on Fundamental Aspects of Vortex Motion, Tokyo (ed. H. Hasimoto & T. Kambe). North-Holland.
Melander, M. & Zabusky, N. 1989 Three dimensional vortex tube reconnection; morphology for orthogonally offset tubes. Physica D 37, 555.Google Scholar
Moore, D. W. & Saffman, P. G. 1971 Structure of a line vortex in an imposed strain. In Aircraft Wake Turbulence (ed. J. Olsen, A. Goldberg & N. Rogers), p. 1. Plenum.
Moore, D. W. & Saffman, P. G. 1972 The motion of a vortex filament with axial flow. Phil. Trans. R. Soc. Lond. 272, 403.Google Scholar
Morf, R. H., Orszag, S. A. & Frisch, U. 1980 Spontaneous singularity in three-dimensional, inviscid, incompressible flow. Phys. Rev. Lett. 44, 572.Google Scholar
Oshima, Y. & Asaka, S. 1977 Interaction of two vortex’ rings along parallel axes in air. J. Phys. Soc. Japan 42, 708.Google Scholar
Pumir, A. & Kerr, R. 1988 Numerical simulation of interacting vortex tubes. Phys. Rev. Lett. 58, 1636.Google Scholar
Pumir, A. & Siggia, E. D. 1990 Collapsing solutions to the 3-D Euler Equations. Phys. Fluids A 2, 220.Google Scholar
Saffman, P. G. 1990 A model of vortex reconnection. J. Fluid Mech. 212, 395.Google Scholar
Schatzle, P. 1987 An experimental study of fusion of vortex rings. PhD thesis, Graduate Aeronautics Laboratory, California Institute of Technology.
Siggia, E. D. 1985 Collapse and amplification of a vortex filament. Phys. Fluids 28, 794.Google Scholar
Siggia, E. D. & Pumir, A. 1987 Vortex dynamics and the existence of solutions to the Navier–Stokes equations. Phys. Fluids 30, 1606.Google Scholar
Van Dyke, M. 1982 An Album of Fluid Motion. Stanford: Parabolic.