Interaction dynamics of gap flow with vortex-induced vibration in side-by-side cylinder arrangement

A numerical investigation of the vortex-induced vibration (VIV) in a side-by-side circular cylinder arrangement has been performed in a two-dimensionallaminar flow environment. One of the cylinders is elastically mounted and only vibrates in the transverse direction, while its counterpart remains stationary in a uniformflow stream. When the gap ratio is sufficiently small, the flip-flopping phenomenon of the gapflow can be an additional time-dependent interference to theflow field. This phenomenon was reported in the experimental work of Bearman and Wadcock [ “The interaction between a pair of circular cylinders normal to a stream,” J. Fluid Mech.61(3), 499 –511 (1973)] in a side-by-side circular cylinder arrangement, in which the gapflow deflects toward one of the cylinders and switched its sides intermittently. Albeit one of the two cylinders is free to vibrate, the flip-flop of a gapflow during VIV dynamics can still be observed outside the lock-in region. The exact moments of the flip-flop phenomenon due to spontaneous symmetry breaking are observed in this numerical study. The significant characteristicvortex modes in the near-wake region are extracted via dynamicmodal analysis and the interference between the gapflow and VIV is found to be mutual. In a vibrating side-by-side arrangement, the lock-in region with respect to reduced velocity becomes narrower due to the interference from its stationary counterpart. The frequency lock-in occurs and ends earlier than th...
Source: Physics of Fluids - Category: Physics Authors: Source Type: research