Effect of mass ratio on flow-induced vibration of a trapezoidal cylinder at low Reynolds numbers

Abstract

A numerical study of the effect of the mass ratio (M*) on the flow-induced vibration of a trapezoidal cylinder at low Reynolds numbers (Re = 60–250) is presented. The response characteristics are divided into three classes with varying mass ratios (2, 5, 10, 20, 30, 50, and 100): (1) class I for low mass ratios (M* = 2), (2) class II for medium mass ratios (5 ≤ M* 200), and the peak amplitudes and ranges of lock-in in VIV become much smaller with an increase in M*. Among these three classes, similar distinctions are also observed in the hydrodynamic forces. In terms of X–Y trajectories, three types are found in class I, while there are only two and one in classes II and III, respectively. Wake structures are also investigated for these classes.