TY - JOUR

T1 - Pivot location and mass ratio effects on flow-induced vibration of a fully passive flapping foil

AU - Wang, Zhuo

AU - Du, Lin

AU - Zhao, Jisheng

AU - Thompson, Mark C.

AU - Sun, Xiaofeng

PY - 2021/1

Y1 - 2021/1

N2 - This paper reports on an extensive numerical investigation of the effects of pivot location and mass ratio (m∗= solid/fluid mass) on flow-induced vibration (FIV) of a foil undergoing fully passive two-degree-of-freedom (2-DOF) plunging and pitching motion in a two-dimensional free-stream flow. Here, the normalised pivot location is defined by x=xp∕c, with c the foil length and xp the distance to the foil leading edge. A comprehensive set of numerical simulations were conducted employing an Immersed Boundary Method at a Reynolds number of 400. By analysing the FIV dynamics for three selected mass ratios, m∗=5, 20 and 200, at two pivot locations, x=0.35 and 0.50, it is found that there are two types (type-I and type-II) of FIV responses, one is primarily a driven static instability while the other is strongly associated with vortex shedding. Interestingly, for x=0.50, which is close to the mass centre, increasing the mass ratio can favour suppression of the chaotic response. Importantly, it is shown that there exists a critical mass ratio, above which the foil oscillations are suddenly suppressed. The findings indicate that the combined effects of eccentricity and mass ratio on the foil dynamics can be profound.

AB - This paper reports on an extensive numerical investigation of the effects of pivot location and mass ratio (m∗= solid/fluid mass) on flow-induced vibration (FIV) of a foil undergoing fully passive two-degree-of-freedom (2-DOF) plunging and pitching motion in a two-dimensional free-stream flow. Here, the normalised pivot location is defined by x=xp∕c, with c the foil length and xp the distance to the foil leading edge. A comprehensive set of numerical simulations were conducted employing an Immersed Boundary Method at a Reynolds number of 400. By analysing the FIV dynamics for three selected mass ratios, m∗=5, 20 and 200, at two pivot locations, x=0.35 and 0.50, it is found that there are two types (type-I and type-II) of FIV responses, one is primarily a driven static instability while the other is strongly associated with vortex shedding. Interestingly, for x=0.50, which is close to the mass centre, increasing the mass ratio can favour suppression of the chaotic response. Importantly, it is shown that there exists a critical mass ratio, above which the foil oscillations are suddenly suppressed. The findings indicate that the combined effects of eccentricity and mass ratio on the foil dynamics can be profound.

KW - Eccentricity

KW - Fluid–structure interaction

KW - Mass ratio

UR - http://www.scopus.com/inward/record.url?scp=85095708471&partnerID=8YFLogxK

U2 - 10.1016/j.jfluidstructs.2020.103170

DO - 10.1016/j.jfluidstructs.2020.103170

M3 - Article

AN - SCOPUS:85095708471

VL - 100

JO - Journal of Fluids and Structures

JF - Journal of Fluids and Structures

SN - 0889-9746

M1 - 103170

ER -