Enhanced Vortex Shedding in a 183 m Industrial Chimney

Abstract

This paper shows how numerical simulation can be used to explain the dynamic behaviour of two chimneys in close proximity. For similar wind speeds, the dynamic response of the leeward chimney depends on alignment of wind directions with a vector from the new to the old chimney. Evidence is presented that Enhanced Vortex Shedding (EVS) caused significant vibrations on the old 183 m high reinforced concrete chimney at Rugeley Power Station during several years of coexistence with its replacement. Strong vibrations were observed under certain conditions of wind speed and direction during construction of the new chimney, consistent with predictions of a performance study. To avoid excessive response of the old chimney during its final years of coexistence with the new one, a tuned mass damper (TMD) was installed together with a monitoring system to verify the effectiveness of the TMD. The monitoring system allowed confirming that vibration levels for winds from the south-west direction of the new chimney were higher than for similar wind speeds from other directions, a finding validated by numerical simulation using advanced computational fluid dynamics (CFD) and fluid-structure interaction (FSI) techniques.