Abstract
For a body moving within a fluid, its shape and the manner in which it morphs greatly impact the energy transfer between it and the flow. In vanishing bodies, vorticity is globally shed, while added mass-related energy is released into the fluid. We investigate square-tipped, streamlined-tipped, and hollow foils towed at \(10^{\circ }\) angle of attack and quickly retracted in the span-wise direction, as generic models of bodies of different form undergoing rapid shape and volume change. Particle image velocimetry shows that large differences exist in their globally shed wakes. The retracting square-tipped foil forms a wake with energy in excess of the potential flow estimate before retraction starts; the extra energy results in the formation of an additional vortex ring that adds unsteadiness and complexity to the form of the wake. The streamlined-tipped foil avoids creating such ring vortices, but sheds a much less energetic wake: numerical simulation shows that energy is transferred back to the foil during the retraction phase through a thrust force. Circulation calculations show that energy transfer is enabled by the gradual shape change in this foil and is associated with simultaneous pressure gradient-induced and vorticity tilting-induced vorticity annihilation. Finally, the hollow foil combines the advantages of near-complete transfer of the original added mass-related energy to the wake and absence of a vortex ring formation, resulting in an energetic and also cleanly-evolving, stable wake. Hence, modest differences in morphing body shape are shown to result in significantly different flow patterns.
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Alam, M.M., Zhou, Y., Yang, H.X., Guo, H., Mi, J.: The ultra-low Reynolds number airfoil wake. Exp. Fluids 48(1), 81–103 (2010)
Biesheuvel, A., Hagmeijer, R.: On the force on a body moving in a fluid. Fluid Dyn. Res. 38(10), 716–742 (2006)
Burgers, J.M.: On the resistance of fluids and vortex motion. Koninklijke Nederlandsche Akademie van Wetenschappen Proceedings, vol. 23, pp. 774–782 (1920)
Childress, S., Vanderberghe, N., Zhang, J.: Hovering of a passive body in an oscillating airflow. Phys. Fluids 18, 117103 (2006)
Dickinson, M.: Animal locomotion: how to walk on water? Nature 424, 621–622 (2003)
Dong, H., Bozkurttas, M., Mittal, R., Madden, P., Lauder, G.V.: Computational modelling and analysis of the hydrodynamics of a highly deformable fish pectoral fin. J. Fluid Mech. 645, 345373 (2010)
Drucker, E.G., Lauder, G.V.: A hydrodynamic analysis of fish swimming speed: wake structure and locomotor force in slow and fast labriform swimmers. J. Exp. Biol. 203, 2379–2393 (2000)
Eames, I.: Disappearing bodies and ghost vortices. Phil. Trans. R. Soc. A 366, 2219–2232 (2008)
Hedenstrom, A., Johansson, L.C., Spedding, G.R.: Bird or bat: comparing airframe design and flight performance. Bioinsp. Biomim. 4, 015001 (2006)
Hsieh, S.T., Lauder, G.V.: Running on water: three-dimensional force generation by basilisk lizards. Proc. Nat. Acad. Sci. 101, 16784–16788 (2004)
Hu, D.L., Bush, J.W.M.: The hydrodynamics of water-walking arthropods. J. Fluid Mech. 644, 5–33 (2010)
Huffard, C.L.: Locomotion by abdopus aculeatus (cephalopoda: Octopodidae): walking the line between primary and secondary defenses. J. Exp. Biol. 209, 3697–3707 (2006)
Hunt, J.C.R., Eames, I.: The disappearance of viscous and laminar wakes in complex flows. J. Fluid Mech. 457, 111–132 (2002)
Jeong, J., Hussain, F.: On the identification of a vortex. J. Fluid Mech. 285, 69–94 (1995)
Kanso, E.: Swimming due to transverse shape deformations. J. Fluid Mech. 631, 127148 (2009)
Klein, F.: Über die Bildung von Wirbeln in reibungslosen Flüssigkeiten. Z. Mathematik & Physik 58, 259–262 (1910)
Lighthill, J.: Mathematica biofluiddynamics. Society for Industrial and Applied Mathematics (1975)
Lighthill, J.: An Informal Introduction to Theoretical Fluid Mechanics. IMA monograph series, no. 2. Oxford University Press (1986)
Lindhe Norberg, U.M., Winter, Y.: Wing beat kinematics of a nectar-feeding bat, Glossophaga soricina, flying at different flight speeds and Strouhal numbers. J. Exp. Biol. 209, 38873897 (2006)
Maertens, A.P., Weymouth, G.D.: Accurate Cartesian-grid simulations of near-body flows at intermediate Reynolds numbers. Comput. Methods Appl. Mech. Eng. 283, 106–129 (2015)
Milne-Thomson, L.M.: Theoretical Hydrodynamics. Dover Publications Inc (1968)
Morton, B.R.: The generation and decay of vorticity. Geophys. Astrophys. Fluid Dyn. 28(3–4), 277–308 (1984)
Muller, U.K., Lentink, D.: Turning on a Dime. Science 306, 1899–1990 (2004)
Packard, A.: Jet propulsion and the giant fibre response of loligo. Nature 221, 875–877 (1969)
Polet, D.T., Rival, D.E., Weymouth, G.D.: Unsteady dynamics of rapid perching manoeuvres. J. Fluid Mech. (2015)
Raffel, M., Willert, C.E., Wereley, S.T., Kompenhans, J.: Particle Image Velocimetry: A Practical Guide; with 42 tables. Berlin (u.a.), Springer (2007)
Ramamurti, R., Sandberg, W.C., Lohner, R., Walker, J.A., Westneat, M.W.: Fluid dynamics of aquatic flight in the bird wrasse: three dimensional unsteady computations with fin deformation. J. Exp. Biol. 205, 29973008 (2002)
Spagnolie, S.E., Shelley, M.J.: Shape changing bodies in fluid: hovering, ratcheting, and bursting. Phys. Fluids 21, 013103 (2009)
Taylor, G.I.: Formation of a vortex ring by giving an impulse to a circular disk and then dissolving it away. J. Appl. Phys. 24, 104 (1953)
Weymouth, G.D., Triantafyllou, M.S.: Global vorticity shedding for a shrinking cylinder. J. Fluid Mech. 702(July), 470–487 (2012)
Weymouth, G.D., Triantafyllou, M.S.: Ultra-fast escape of a deformable jet-propelled body. J. Fluid Mech. 721, 367–385 (2013)
Weymouth, G.D., Yue, D.K.P.: Boundary data immersion method for Cartesian-grid simulations of fluid-body interaction problems. J. Comput. Phys. 230(16), 6233–6247 (2011)
Wibawa, M.S., Steele, S.C., Dahl, J.M., Rival, D.E., Weymouth, G.D., Triantafyllou, M.S.: Global vorticity shedding for a vanishing wing. J. Fluid Mech. 695, 112–134 (2012)
Wu, J.Z., Wu, J.M.: Interactions between a solid surface and a viscous compressible flow field. J. Fluid Mech. 254, 183–211 (1993)
Wu, J.Z., Wu, J.M.: Boundary vorticity dynamics since Lighthill’s 1963 article: review and development. Theoret. Comput. Fluid Dyn. 10(1–4), 459–474 (1998)
Wu, J.Z., Ma, H.Y., Zhou, M.D.: Vorticity and Vortex Dynamics: with 291 figures. Springer-Verlag, Berlin (2006)
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Steele, S.C., Weymouth, G.D., Dahl, J.M., Triantafyllou, M.S. (2016). Principles of Wake Energy Recovery and Flow Structure in Bodies Undergoing Rapid Shape Change. In: Braza, M., Bottaro, A., Thompson, M. (eds) Advances in Fluid-Structure Interaction. Notes on Numerical Fluid Mechanics and Multidisciplinary Design, vol 133. Springer, Cham. https://doi.org/10.1007/978-3-319-27386-0_2
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DOI: https://doi.org/10.1007/978-3-319-27386-0_2
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