The cross-wind excitation of bluff structures and the incident turbulence mechanism

The excitation of a structure by wind action can be conveniently considered under the divisions 'along-wind excitation' and 'cross-wind excitation'. In the case of along-wind excitation, it has been shown (primarily from the work of Davenport [1967] and Vickery [1971]) that the excitation results almost entirely from the action of the longitudinal velocity fluctuations. As a result, analytical prediction techniques for along-wind excitation have become highly developed.

On the other hand, the cross-wind excitation process has proved to be extremely complex and, as Melbourne points out in his 1975 review paper on cross-wind aerodynamics, there is as yet no generalised analytical method available to calculate the cross-wind response of structures. This is despite the fact that the cross-wind excitation is often the major source of excitation for many real structures, such as bridge decks and tall buildings.