A coupled parametric-CFD study for determining ages of downbursts through investigation of different field parameters

Downburst wind loads pose great threats to many structural systems and industrial aviation, especially large structures. Previous investigations on downburst wind events focused on steady state simulation and were then developed for unsteady state simulation. The total age of downburst events is rarely investigated, but the importance of the event period arises during any study of large extended structural systems such as transmission line systems, where they can experience most of the downburst period. In addition, the accumulated temporal profiles of downburst wind speeds are needed for dynamic analysis and for developing the intensity decay function that can simulate the temporal profile of the event. In this paper a developed parametric study is coupled with numerical CFD simulations to investigate several observed downburst events. The different parameters of the downburst events such as the total age, intensity period, decay period, downburst diameter, initial location, path direction and parent storm translation speed have been estimated by relating the recorded data to the coupled parametric-CFD study. Then an accurate period for depicting the actual age of downburst events is presented and a relationship between downburst sizes and their ages is developed. (C) 2013 Elsevier Ltd. All rights reserved.