Three-dimensional flow structures and vorticity control in fish-like swimming

By Qiang Zhu, M. J. Wolfgang, Dick K. P. Yue, Michael S. Triantafyllou. Journal of Fluid Mechanics, 2002

202 citations recorded by the source corpus.

We employ a three-dimensional, nonlinear inviscid numerical method, in conjunction with experimental data from live fish and from a fish-like robotic mechanism, to establish the three-dimensional features of the flow around a fish-like body swimming in a straight line, and to identify the principal mechanisms of vorticity control employed in fish-like swimming. The computations contain no structural model for the fish and hence no recoil correction. First, we show the near-body flow structure produced by the travelling-wave undulations of the bodies of a tuna and a giant danio. As revealed in cross-sectional planes, for tuna the flow contains dominant features resembling the flow around a two-dimensional oscillating plate over most of the length of the fish body. For the giant danio, on the other hand, a mixed longitudinal–transverse structure appears along the hind part of the body. We also investigate the interaction of the body-generated vortices with the oscillating caudal fin and with tail-generated vorticity. Two distinct vorticity interaction modes are identified: the first mode results in high thrust and is generated by constructive pairing of body-generated vorticity with same-sign tail-generated vorticity, resulting in the formation of a strong thrust wake; the second corresponds to high propulsive efficiency and is generated by destructive pairing of body-generated vorticity with opposite-sign tail-generated vorticity, resulting in the formation of a weak thrust wake.

Subfields: Aerospace Engineering, Computational Mechanics

View Paper: https://www.semanticscholar.org/paper/6b5018381c68377ca79fb93cd5a06bee4931f98d

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Citations in the corpus

Hydrodynamics of swimming in stingrays: numerical simulations and the role of the leading-edge vortex (2016, background): “…Streitlien & Barrett 1998; Lewin & Haj-Hariri 2003; Dong, Mittal & Najjar 2006) – see the review by Triantafyllou, Techet & Hover (2004) – and fish-like swimmers (Wolfgang et al. 1999; Nauen & Lauder 2001; Zhu et al. 2002; Borazjani & Sotiropoulos 2008) – see the review by Fish & Lauder (2006).”
A hybrid Cartesian/immersed boundary method for simulating flows with 3D, geometrically complex, moving bodies (2005, methodology): “To mimic such motion, we prescribe the lateral displacement of the fish body in terms of a traveling wave of varying amplitude [62] as follows:”
Numerical Simulation of a Flapping Foil with Chordwise or Spanwise Flexibility (2007, background): “The strength of the newly shed wake is determined by the explicit Kutta condition [17,18]; that is, the new wake strength w at the trailing edge equals the instantaneous difference of body influence potential b between the upper and lower surfaces near the edge.”
Morphology and experimental hydrodynamics of fish fin control surfaces (2004, background): “1) Dorsal Fin Function: The dorsal fi no ffish plays an active role during both propulsion and maneuvering (e.g., [13], [89]‐[ 91 ]).”
Flapping Wing Aerodynamics: Progress and Challenges (2008, unknown): “[68].”
Biomimetic survival hydrodynamics and flow sensing (2015, background): “The irrotational-like flow at the preparatory phase, consisting of dipole-like structures at any particular planar cut that is perpendicular to the mid-line curve (as shown in Zhu et al. (2002)), transitions eventually to form two vortex rings.”