Title: A further study of inverted hydrodynamic drafting for flow past two flexible filaments in tandem arrangement

Authors: Fangfang Xie; Jian Deng

Addresses: School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China ' School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China

Abstract: Two tandem filaments in a uniform flow are simulated by using a penalty immersed boundary method. First, we investigate two identical filaments, duplicating the 'inverted drafting'. We then fix the structural parameters of the leader while vary that of the follower in kb2 and ρs2. It is found as the follower is stiffer or lighter than the leader, the follower flaps in larger amplitude than the leader. While the drag force acting on the follower is lower than that of the leader, which is in conflict with the so-called 'inverted drafting'. However, if we compare the dynamics of the follower to that of an isolated filament with the same structural properties, the 'inverted drafting' holds again. Furthermore, we investigate the characteristic of energy transfer between filaments and their surrounding fluid. The correlation parameter Clv indicates the follower extracts more energy than the leader except for the cases with ρs2 ≤ 0.2.

Keywords: fluid-structure interaction; flexible filaments; inverted hydrodynamic drafting.

DOI: 10.1504/PCFD.2018.091699

Progress in Computational Fluid Dynamics, An International Journal, 2018 Vol.18 No.3, pp.164 - 176

Received: 08 Jun 2016
Accepted: 05 Jul 2016

Published online: 25 Apr 2018 *

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