Fluid Dynamics of Biomimetic Pectoral Fin Propulsion Using Immersed Boundary MethodReport as inadecuate




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Applied Bionics and Biomechanics - Volume 2016 2016, Article ID 2721968, 22 pages -

Research ArticleScience and Technology on Underwater Vehicle Laboratory, Harbin Engineering University, Harbin 150001, China

Received 8 December 2015; Revised 3 May 2016; Accepted 7 June 2016

Academic Editor: Cecilia Laschi

Copyright © 2016 Ningyu Li and Yumin Su. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Numerical simulations are carried out to study the fluid dynamics of a complex-shaped low-aspect-ratio pectoral fin that performs the labriform swimming. Simulations of flow around the fin are achieved by a developed immersed boundary IB method, in which we have proposed an efficient local flow reconstruction algorithm with enough robustness and a new numerical strategy with excellent adaptability to deal with complex moving boundaries involved in bionic flow simulations. The prescribed fin kinematics in each period consists of the power stroke and the recovery stroke, and the simulations indicate that the former is mainly used to provide the thrust while the latter is mainly used to provide the lift. The fin wake is dominated by a three-dimensional dual-ring vortex wake structure where the partial power-stroke vortex ring is linked to the recovery-stroke ring vertically. Moreover, the connection of force production with the fin kinematics and vortex dynamics is discussed in detail to explore the propulsion mechanism. We also conduct a parametric study to understand how the vortex topology and hydrodynamic characteristics change with key parameters. The results show that there is an optimal phase angle and Strouhal number for this complicated fin. Furthermore, the implications for the design of a bioinspired pectoral fin are discussed based on the quantitative hydrodynamic analysis.





Author: Ningyu Li and Yumin Su

Source: https://www.hindawi.com/



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