Hostname: page-component-78c5997874-v9fdk Total loading time: 0 Render date: 2024-11-13T01:41:39.747Z Has data issue: false hasContentIssue false

Flapping dynamics of a flag in a uniform stream

Published online by Cambridge University Press:  22 May 2007

BENJAMIN S. H. CONNELL
Affiliation:
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
DICK K. P. YUE*
Affiliation:
Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
*
Author to whom correspondence should be addressed: yue@mit.edu

Abstract

We consider the flapping stability and response of a thin two-dimensional flag of high extensional rigidity and low bending rigidity. The three relevant non-dimensional parameters governing the problem are the structure-to-fluid mass ratio, μ = ρsh/(ρfL); the Reynolds number, Rey = VL/ν; and the non-dimensional bending rigidity, KB = EI/(ρfV2L3). The soft cloth of a flag is represented by very low bending rigidity and the subsequent dominance of flow-induced tension as the main structural restoring force. We first perform linear analysis to help understand the relevant mechanisms of the problem and guide the computational investigation. To study the nonlinear stability and response, we develop a fluid–structure direct simulation (FSDS) capability, coupling a direct numerical simulation of the Navier–Stokes equations to a solver for thin-membrane dynamics of arbitrarily large motion. With the flow grid fitted to the structural boundary, external forcing to the structure is calculated from the boundary fluid dynamics. Using a systematic series of FSDS runs, we pursue a detailed analysis of the response as a function of mass ratio for the case of very low bending rigidity (KB = 10−4) and relatively high Reynolds number (Rey = 103). We discover three distinct regimes of response as a function of mass ratio μ: (I) a small μ regime of fixed-point stability; (II) an intermediate μ regime of period-one limit-cycle flapping with amplitude increasing with increasing μ; and (III) a large μ regime of chaotic flapping. Parametric stability dependencies predicted by the linear analysis are confirmed by the nonlinear FSDS, and hysteresis in stability is explained with a nonlinear softening spring model. The chaotic flapping response shows up as a breaking of the limit cycle by inclusion of the 3/2 superharmonic. This occurs as the increased flapping amplitude yields a flapping Strouhal number (St = 2Af/V) in the neighbourhood of the natural vortex wake Strouhal number, St ≃ 0.2. The limit-cycle von Kármán vortex wake transitions in chaos to a wake with clusters of higher intensity vortices. For the largest mass ratios, strong vortex pairs are distributed away from the wake centreline during intermittent violent snapping events, characterized by rapid changes in tension and dynamic buckling.

Type
Papers
Copyright
Copyright © Cambridge University Press 2007

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: Applied Physical Sciences Corporation, Groton, CT 06340, USA.

References

REFERENCES

Allen, J. J. & Smits, A. J. 2001 Energy harvesting eel. J. Fluids Struct. 15, 629640.CrossRefGoogle Scholar
Argentina, M. & Mahadevan, L. 2005 Fluid-flow-induced flutter of a flag. Proc. Natl Acad. Sci. 102, 18291834.CrossRefGoogle ScholarPubMed
Armfield, S. W. 1991 Finite difference solutions of the Navier–Stokes equations on staggered and non-staggered grids. Comput. & Fluids 20, 117.CrossRefGoogle Scholar
Chorin, A. J. 1968 Numerical solution of the Navier–Stokes equations. Math. Comp.CrossRefGoogle Scholar
Coene, R. 1992 Flutter of slender bodies under axial stress. Appl. Sci. Res. 49, 175187.CrossRefGoogle Scholar
Connell, B. S. H. 2006 Numerical investigation of the flow-body interaction of thin flexible foils and ambient flow. PhD thesis, Massachusetts Institute of Technology, Cambridge, MA.Google Scholar
Dickinson, M. H. & Gotz, K. G. 1993 Unsteady aerodynamic performance of model wings at low Reynolds numbers. J. Expl Biol. 174, 4564.CrossRefGoogle Scholar
Drazin, P. G. 1992 Nonlinear Systems, chap. 7. Cambridge University Press.CrossRefGoogle Scholar
Dutsch, H., Durst, F., Becker, S. & Lienhart, H. 1998 Low-Reynolds-number flow around an oscillating circular cylinder at low Keulegan–Carpenter numbers. J. Fluid Mech. 360, 249271.CrossRefGoogle Scholar
Farnell, D. J. J., David, T. & Barton, D. C. 2004a Coupled states of flapping flags. J. Fluids Struct. 19, 2936.CrossRefGoogle Scholar
Farnell, D. J. J., David, T. & Barton, D. C. 2004b Numerical simulations of a filament in a flowing soap film. Intl J. Numer. Meth. Fluids 44, 313330.CrossRefGoogle Scholar
Gobat, J. I., Grosenbaugh, M. A. & Triantafyllou, M. S. 2002 Generalized-alpha time integration solutions for hanging chain dynamics. J. Engng Mech. 128, 677687.Google Scholar
Gray, J. 1933 Studies in animal locomotion. I. The movement of fish with special reference to the eel. J. Expl Biol. 10, 88104.CrossRefGoogle Scholar
Howell, C. T. & Triantafyllou, M. S. 1993 Stable and unstable nonlinear resonant response of hanging chains: Theory and experiment. Proc. R. Soc. Lond. A 440, 345364.Google Scholar
Kawamura, T. & Kuwahara, K. 1984 Computation of high Reynolds number flow around a circular cylinder with surface roughness. AIAA Paper 840340.Google Scholar
Koh, C. G., Zhang, Y. & Quek, S. T. 1999 Low-tension cable dynamics: Numerical and experimental studies. J. Engng Mech. 125, 347354.Google Scholar
Kunz, P. J. & Kroo, I. 2001 Analysis and design of airfoils for use at ultra-low Reynolds numbers. In Fixed and Flapping Wing Aerodynamics for Micro Air Vehicle Applications (ed. Mueller, T. J.), pp. 3560. AIAA.Google Scholar
Li, M. & Tang, T. 2001 A compact fourth-order finite difference scheme for unsteady viscous incompressible flows. J. Sci. Comput. 16, 2945.CrossRefGoogle Scholar
Li, Y. 1997 Wavenumber-extended high-order upwind-biased finite-difference schemes for convective scalar transport. J. Comput. Phys. 133, 235255.CrossRefGoogle Scholar
Liao, J. C., Beal, D. N., Lauder, G. V. & Triantafyllou, M. S. 2003 a Fish exploiting vortices decrease muscle activity. Science 302, 15661569.CrossRefGoogle ScholarPubMed
Liao, J. C., Beal, D. N., Lauder, G. V. & Triantafyllou, M. S. 2003 b The Kármán gait: Novel body kinematics of rainbow trout swimming in a vortex street. J. Expl Biol. 206, 10591073.CrossRefGoogle Scholar
Moretti, P. M. 2003 Tension in fluttering flags. Intl J. Acoust. Vibt. 8, 227230.Google Scholar
Moretti, P. M. 2004 Flag flutter amplitudes. In Flow Induced Vibrations, Paris, July 6–9 2004 (ed. de Langre & Axisa), pp. 113118. Ecole Polytechnique.Google Scholar
Olson, C. L. & Olsson, M. G. 1991 Dynamical symmetry breaking and chaos in Duffing's equation. Am. J. Phys. 59, 907911.CrossRefGoogle Scholar
Paidoussis, M. P. 1966 Dynamics of flexible cylinders in axial flow. J. Fluid Mech. 26, 717751.CrossRefGoogle Scholar
Procaccia, I. 1988 Universal properties of dynamically complex systems: the organization of chaos. Nature 333, 618623.CrossRefGoogle Scholar
Sarpkaya, T. 1979 Vortex-induced oscillations. J. Appl. Mech. 46, 241258.CrossRefGoogle Scholar
Shelley, M., Vandenberghe, N. & Zhang, J. 2005 Heavy flags undergo spontaneous oscillations in flowing water. Phys. Rev. Lett. 94, 094302–1–4.CrossRefGoogle ScholarPubMed
Shen, L., Zhang, X., Yue, D. K. P. & Triantafyllou, M. S. 2003 Turbulent flow over a flexible wall undergoing a streamwise travelling wave motion. J. Fluid Mech. 484, 197221.CrossRefGoogle Scholar
Strikwerda, J. C. 1997 High-order-accurate schemes for incompressible viscous flow. Intl J. Numer. Methods Fluids 24, 715734.3.0.CO;2-E>CrossRefGoogle Scholar
Techet, A. H., Hover, F. S. & Triantafyllou, M. S. 1997 Separation and turbulence control in biomimetic flows. Flow, Turb. Combust. 24, 715734.Google Scholar
Thoma, D. 1939 Das schlenkernde Seil (the oscillating rope). Z. Angew. Math. Mech. 19, 320321.CrossRefGoogle Scholar
Thompson, J. F., Thames, F. C. & Mastin, C. W. 1977 TOMCAT: A code for numerical generation of boundary-fitted curvilinear coordinate systems on fields containing any number of arbitrary two-dimensional bodies. J. Comput. Phys. 24, 274302.CrossRefGoogle Scholar
Triantafyllou, G. S. 1992 Physical condition for absolute instability in inviscid hydroelastic coupling. Phys. Fluids A 4, 544552.CrossRefGoogle Scholar
Triantafyllou, M. S. & Howell, C. T. 1994 Dynamic response of cables under negative tension: an ill-posed problem. J. Sound Vib. 173, 433447.CrossRefGoogle Scholar
Watanabe, Y., Suzuki, S., Sugihara, M. & Sueoka, Y. 2002 An experimental study of paper flutter. J. Fluids Struct. 16, 529542.CrossRefGoogle Scholar
Williamson, C. H. K. & Govardhan, R. 2004 Vortex-induced vibrations. Annu. Rev. Fluid Mech. 36, 413455.CrossRefGoogle Scholar
Williamson, C. H. K. & Roshko, A. 1988 Vortex formation in the wake of an oscillating cylinder. J. Fluids Struct. 2, 355381.CrossRefGoogle Scholar
Wolf, A., Swift, J. B., Swinney, H. L. & Vastano, J. A. 1985 Determining Lyapunov exponents from a time series. Physica D 16, 285317.Google Scholar
Zhang, J., Childress, S., Libchaber, A. & Shelley, M. 2000 Flexible filaments in a flowing soap film as a model for one-dimensional flags in a two-dimensional wind. Nature 408, 835839.CrossRefGoogle Scholar
Zhu, L. & Peskin, C. S. 2002 Simulation of flapping flexible filament in a flowing soap film by the immersed boundary method. J. Comput. Phys. 179, 452468.CrossRefGoogle Scholar
Zhu, L. & Peskin, C. S. 2003 Interaction of two flapping filaments in a flowing soap film. Phys. Fluids 15, 19541960.CrossRefGoogle Scholar
Zhu, Q., Liu, Y., Tjavaras, A. A., Triantafyllou, M. S. & Yue, D. K. P. 1999 Mechanics of nonlinear short-wave generation by a moored near-surface buoy. J. Fluid Mech. 381, 305335.CrossRefGoogle Scholar