Authors: G X Shen G K Tan G J Lai
Publish Date: 2012/11/09
Volume: 28, Issue: 5, Pages: 1494-1508
Abstract
A bionic experimental platform was designed for the purpose of investigating time accurate threedimensional flow field using digital particle image velocimetry DSPIV The wake behind the flapping trail of a robotic fish model was studied at high spatial resolution The study was performed in a water channel A robot fish model was designed and built The model was fixed onto a rigid support framework using a cablesupporting method with twelve stretched wires The entire tail of the model can perform prescribed motions in two degrees of freedom mainly in carangiform mode by driving its afterbody and lunate caudal fin respectively The DSPIV system was set up to operate in a translational manner measuring velocity field in a series of parallel slices Phase locked measurements were repeated for a number of runs allowing reconstruction of phase average flow field Vortex structures with phase history of the wake were obtained The study reveals some new and complex threedimensional flow structures in the wake of the fish including “reverse hairpin vortex” and “reverse Karman SH vortex rings” allowing insight into physics of this complex flow
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