Interference effect on super large twin cooling towers exposed to stationary tornado-like vortices

Abstract

A comprehensive investigation was conducted aiming at the interference effects on wind pressure distribution, aerodynamics characteristics, structural stability and reinforcement areas of super large twin cooling towers exposed to tornado-like vortices, and the effects of swirl ratios of tornados, grouped tower layouts, and relative central distances between the towers and the tornado were analysed based on a tornado-like vortex simulator. Two types of rigid model wind tunnel experiments were constructed for base forces and wind pressure distribution measurements. The experimental results demonstrate that the interference effects on base forces and local wind pressures are significantly influenced by the swirl ratios, central distances, and grouped tower layouts, etc. Moreover, the layout with a tornado located on the side of tandem twin cooling towers (along with the tornado translation direction being perpendicular to the central axis of the tandem combined twin cooling towers) is the most unfavourable, resulting in obvious amplification effects on base forces and local wind pressures compared with an isolated tower, and the maximum of interference factors (IFs) is 1.68 and 1.41 for the along-wind total wind force coefficient and minimal net mean pressure coefficient respectively. Subsequently, local stability indices and time-variant dynamic reinforcement envelopes were selected as the other evaluation criteria for estimating the interference effects on the cooling towers exposed to the tornado-like vortices, and the interference effects result in enlargements of the structural responses with the maximal IF of 1.36 for the inside meridional reinforcement. Finally, the various interference criteria at aerodynamic loading and structural reinforcement aspects were contrastive analysed, showing that the criterion of time-variant dynamic reinforcement area envelopes is a more reasonable criterion for evaluating the interference effects on the super large cooling towers exposed to the tornado-like vortices. This investigation aims to contribute to a better understanding of the wind-related effects of the cooling towers exposed to extreme non-synoptic winds, particularly tornadic vortex impacts.