Abstract:
Studies were initiated for clear interpretation of the influence of the fundamental frequency,
f0, on the wind dynamic effects of hyperbolic cooling towers (HCTs). Based on the preceding wind dynamic calculation in time domain and the features of dynamic effects, a new method was proposed to adjust
f0 and brought into the following operation. In this new method, the material elastic modulus
E was changed to get different
f0's and corresponding wind dynamic effects, especially the resonance component,
σR. The advantages of this method are also presented. The results show that the coupling effect between the resonance and background components,
σR and
σB, obtained in time domain is negligible no matter what value the
f0 takes.
σR increases with the decrease of
f0, especially when
f0 is less than 0.7 Hz. However, the total gust response,
σT, increases more slowly with the decrease of
f0 because the significant contribution of
σB and
σB does not change with
f0. Therefore,
σT shows quick increase only if
f0 is less than 0.5 Hz. There are two reasons for the increase of
σR when
f0 decreases: 1) the wind spectrum increases with the decrease of frequency and 2) more resonant modes would be excited. A parameter
Rp=(1/
f0×(1/
f0-1/2)), which could cover the above two reasons, was proposed for convenient evaluation of
σR. A linear relationship is found between
σR of all responses and the parameter
RP.