The propulsive dynamics of a flexible undulating foil in a self-propelled swimming configuration near a wall is studied experimentally. Measurements of the swimming speed and the propulsive force are presented, together with image acquisition of the kinematics of the foil and particle image velocimetry (PIV) in its wake. The presence of the wall enhances the cruising velocity in some cases up to 25% and the thrust by a 45% , for swept angles of 160 and 240°. The physical mechanisms underlying this effect are discussed by studying the vorticity dynamics in the wake of the foil. Proper orthogonal decomposition is applied to the PIV measurements in order to analyse the kinetic energy modal distribution in the flow and to relate it to the propulsion generated by the foil.
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http://dx.doi.org/10.1088/1748-3190/10/1/016003 | DOI Listing |
PLoS Biol
July 2020
Experimental Zoology Group, Department of Animal Sciences, Wageningen University, Wageningen, the Netherlands.
Most fish swim with body undulations that result from fluid-structure interactions between the fish's internal tissues and the surrounding water. Gaining insight into these complex fluid-structure interactions is essential to understand how fish swim. To this end, we developed a dedicated experimental-numerical inverse dynamics approach to calculate the lateral bending moment distributions for a large-amplitude undulatory swimmer that moves freely in three-dimensional space.
View Article and Find Full Text PDFJ Exp Biol
September 2016
Vassar College, Department of Biology, 124 Raymond Avenue, Poughkeepsie, NY 12604, USA Vassar College, Department of Cognitive Science, 124 Raymond Avenue, Poughkeepsie, NY 12604, USA.
During swimming in dogfish sharks, Squalus acanthias, both the intervertebral joints and the vertebral centra undergo significant strain. To investigate this system, unique among vertebrates, we cyclically bent isolated segments of 10 vertebrae and nine joints. For the first time in the biomechanics of fish vertebral columns, we simultaneously characterized non-linear elasticity and viscosity throughout the bending oscillation, extending recently proposed techniques for large-amplitude oscillatory shear (LAOS) characterization to large-amplitude oscillatory bending (LAOB).
View Article and Find Full Text PDFBioinspir Biomim
January 2015
Department of Mechanical Engineering, Universitat Rovira i Virgili, E-43007 Tarragona, Spain.
The propulsive dynamics of a flexible undulating foil in a self-propelled swimming configuration near a wall is studied experimentally. Measurements of the swimming speed and the propulsive force are presented, together with image acquisition of the kinematics of the foil and particle image velocimetry (PIV) in its wake. The presence of the wall enhances the cruising velocity in some cases up to 25% and the thrust by a 45% , for swept angles of 160 and 240°.
View Article and Find Full Text PDFJ Fish Biol
December 2011
Department of Zoology, University of British Columbia, British Columbia, V6T 1Z4 Canada.
A form of large-amplitude elongated-body theory appropriate for the analysis of undulatory fins attached to a rigid body of elliptical section suggests a benefit due to momentum enhancement relative to the fins on their own. This theoretical prediction is experimentally confirmed for the first time. Theoretical momentum enhancement factors for Diodon holocanthus (2.
View Article and Find Full Text PDFJ Exp Biol
April 2008
Experimental Zoology Group, Wageningen Institute of Animal Sciences, Wageningen University, Marijkeweg 40, 6709 PG Wageningen, The Netherlands.
The fast muscle fibres in the anterior trunk of teleost fish are primarily responsible for large amplitude undulatory swimming motions. Previous theoretical studies suggested that the near-helical arrangement of these fibres results in a (fairly) uniform distribution of fibre strain and work output during swimming. However, the underlying simplifications of these studies precluded unequivocal support for this hypothesis.
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