Chordwise flexible aft-tail suppresses jet-switching by reinstating wake periodicity in a flapping foil

The effect of a chordwise flexible aft-tail rigid heaving aerofoil on the dynamical transitions trailing-wake is studied here. two-way coupled fluid–solid dynamics simulated using an in-house fluid–structure interaction (FSI) platform, comprising discrete forcing immersed boundary method based incompressible Navier–Stokes solver, weakly with finite difference structural solver. FSI in comparison to corresponding tail configuration. For latter, mild jet-switching due quasi-periodic movement wake vortices gives way vigorous as state intermittency, where behaviour gets interspersed chaotic windows. Introduction moderately regularises this intermittent dynamics, eliminating jet-switching. exhibits deflected reverse Kármán pattern fluctuating angles, governed by quasi-periodicity. With highly (very low rigidity), shows almost symmetric street periodicity restored. Flexibility next controlled changing its length, and flow regularised retained for moderate rigidity increased length. Different states are established through robust nonlinear tools. underlying flow-field behaviour, instrumental suppressing phenomenon, identified detailed investigation near-field vortex interactions dictated dynamics. A suite measures has also been derived from unsteady field quantify key view understanding mechanism switching subsequent suppression flexibility.