Where is the spectral density of th

Where is the spectral density of the u component of the moving point, ⁄ and ⁄ and other parameters are listed in Table 1. Figure 2 shows the wind spectrummodels of u-component relative to a moving point under different velocities. It is found thatthe auto-PSD regard to a moving point shows significant differences compared to that of thestatic model. The velocity of the point will induce a Doppler effect to the auto-PSD, that is,the wind energy shifts to high frequency with the increase of velocity. However, the energypeak drops as the point speeds up (Li et al. (2017)). Therefore, in the vehicle-bridge unitedsystem, static wind spectrum model and wind spectrum model relative to a moving pointneed to be applied to static simulation points and to the vehicle, respectively.