Numerical Investigations on Suppression of Aeolian Vibrations on a Tall Chimney Using Helical Strakes

Abstract

Tall chimneys subjected to hefty wind loads undergo structural failure catastrophically. This paper aims to investigate the across wind oscillations of the structure during wind and the effect of helical strakes in reducing the wind loads that cause vortex-induced vibrations (VIV). A computationally less expensive RANS simulation used for investigation of wind loads on a tall chimney of height 180 m. The air flow is presumed to be predominantly turbulent and incompressible in the flow field. Shear Stress Transport (SST) k-ω turbulence model is used to capture the turbulent characteristics accurately. The response of the structure to wind loads is investigated for the same velocity on a bare chimney and one fitted with helical strakes. The influence of the helical strakes in reducing the VIVs is analyzed in terms of Strouhal number. It has been observed that the use of helical strakes could significantly reduce wind loads and the magnitude of vortex instabilities around the structure. The obtained results are in reasonable agreement with the available experimental works in the literature.