Experimental investigation of wake flow and wave-vortex coupled vibration of two tandem and cylinders

In order to analyse the upstream riser's effect on downstream riser under different working conditions by model testing, a device which can inhibit the upstream vortex was designed. The experiments focus on the vortex-induced vibration of isolated upstream riser and were carried out with a variety of improved equipments under different flow rate and different spacing conditions. The impact of upstream riser on downstream riser was analysed by observing vortex shedding and measuring model vibration under the conditions of with or without inhibit vortex devices. It is concluded that the vibration state of downstream riser is different from that of isolated standpipe under the influence of upstream standpipe. The lateral vibration of downstream riser without inhibit device first increases and then decreases along with the increase of tube spacing, while it becomes stable beyond some limit of the increase of tube diameter under the condition of installing inhibit devices. ©, 2014, Chinese Vibration Engineering Society. All right reserved.