The effect of the wind load is predominant on the tall and large structures like cooling tower. The study on the deformation of the critical sections of the shell element in the large structures like cooling tower has been skipped on most of the previous research. This paper presents the ovalization pattern of the cooling tower shell in different mode shapes when subjected to axisymmetric wind loading. This paper studies two different models of cooling towers: the 1st model is located in Andal West Bengal, India which is fully hyperbolic in shape, and the 2nd model is the modification of the 1st cooling tower which has the cylindrical portion above the throat level of the 1st cooling tower. Simulation of the cooling tower has been done using the finite element software ABAQUS, the wind load that has been described in the relevant Indian Standard Code has been expressed in terms of Fourier series using the advanced options available in the software. The cross-section distortion of the cooling tower shell in the nonlinear range of the elasticity in different mode shapes has been studied. A comparison of the two types of cooling tower models in terms of stress, displacement and strain is made in this study.

Cooling towers are mainly used for the transferring of waste heat of circulating water in the oil refineries, chemical plants, power stations and other industrial structures to the atmosphere. It is relatively inexpensive and is more reliable in cooling the water of those plants. Different sizes of cooling towers are being constructed nowadays, depending upon the amount of water to be cooled and availability of the construction materials. The tower varies from small units (mechanical draft type) to large structures (natural draft type) with large diameter and height. The cooling efficiency of the cooling tower depends on the height, whereas the shape of the structure makes it stronger against the wind loads acting on it. The greater the height, the more the warm moist air is protected further up and also it maintains an updraft inside the tower. The air inside the tower accelerates as the height rises, so the cross-section has to be reduced with height for non-turbulent flow but a slight opening in the top is found more efficient for dispersal of the moist air. So hyperbolic shape is made wider at the bottom and the top. Also, Natural Draft Cooling Towers (NDCT) are now regarded as environment-friendly and power saving. Beyond the power saving, NDCT offers other advantages such as limited construction area, no mechanical noise (due to fan), limited maintenance and high longevity (generally more than plant life expectancy).

Structural Engineering Journal, Hyperbolic cooling tower, Wind load, Mode shape, Ovalization, ABAQUS