Aerodynamic admittance models for buffeting excitation of high and slender structures

Particularly in highly turbulent flow, conventional linearised descriptions of the originally nonlinear wind-speed-to-wind-force relation may produce a significantly incorrect estimation of the dynamic part of the wind load. The consequences due to different approaches of the aerodynamic admittance function on the fluctuations of the wind loads are studied. The analysis starts from full-scale measurements on a 344 m guyed mast, which is equipped with sensors to measure both the wind turbulence and the resulting wind force. A nonlinear spectral approach is used to estimate the expected wind force spectrum due to the gusty wind. This approach is confined to the correlated parts of the wind turbulence and the associated wind forces, it relates cause and effect. In addition, the influence of the lateral turbulence on the design of high and slender structures is investigated.