Collective locomotion of two-dimensional lattices of flapping plates. Part 1. Numerical method, single-plate case and lattice input power

Silas Alben

doi:10.1017/jfm.2021.6

Abstract

Highlights

Propulsion by flapping foils has garnered considerable interest in recent years, as a bio-inspired alternative to traditional designs for aquatic and aerial vehicles
Moving one panel to the right is a smaller St value, close to where the Froude efficiency is maximized for this range of dimensionless frequencies (Ref), and the larger oncoming flow speed allows the vortex wake to organize into the familiar reverse von Kármán street (Triantafyllou et al 2004)
Compared to the horizontal force, Pin is less sensitive to the oncoming flow speed (i.e. St) and the changes in vortex wake patterns shown in figures 4 and 5

Summary

Introduction

Propulsion by flapping foils has garnered considerable interest in recent years, as a bio-inspired alternative to traditional designs for aquatic and aerial vehicles. Following previous models (Childress & Dudley 2004; Newbolt et al 2019; Oza et al 2019), experiments (Vandenberghe, Childress & Zhang 2006; Becker et al 2015; Ramananarivo et al 2016) and simulations (Wang 2000; Alben & Shelley 2005; Huang 2007; Alben 2008a; Deng & Caulfield 2016, 2018) inspired by biology (Borrell, Goldbogen & Dudley 2005), we consider a particular version of the multiple flapping-foil problem, with simple body geometries and kinematics, that is amenable to a wide (though by no means exhaustive) exploration of parameter space: thin plates that are oscillated vertically and moved horizontally together through a viscous fluid. In a sedimentation simulation, Mucha et al (2004) found that including the boundary region in the simulation had a negligible effect on particle velocity statistics far from the boundary

Numerical method

Single flapping plate

Input power in flapping lattices

Input power for flows through flapping lattices

Findings

Summary and conclusions