Application of Computational Fluid Dynamics (CFD) in predicting the wind loads on tall buildings - a case study

There is a rising demand for tall structures to fulfil the occupancy requirements in congested metropolitan areas. On the other hand there is a considerable demand for monumental structures as tourist attractions in many different parts of the world. Wind behaviour is a key design parameter for such buildings and need to be assessed accurately in the preliminary and secondary design stages. As most of the design codes have their own limitations in providing necessary guidelines for the wind designs such as height limits of the buildings, the existing practice is to conduct wind tunnel tests to determine the wind induced loads on the buildings. However, the costs of wind tunnel tests are comparatively high and conducting wind tunnel tests at preliminary design stage is uneconomical. The shape of the building normally changes a few times during the preliminary stages and this will add to the testing costs. The rapid growth of Computation Fluid Dynamic (CFD) techniques over the last few decades enables Engineers to simulate the wind behaviour around moving objects such as aeroplanes and automobiles. Therefore, use of such methodology to predict wind loads on buildings, especially at the preliminary design stages is essential. This paper discusses a case study that carried out on a typical 208 m tall building with a rectangular geometry. A comparison of results obtained from CFD simulations to the predictions given by the Australian Wind Design Standards (AS1170.2) is presented. In addition the limitations given in different wind design codes are discussed