Wind Field Reconstruction Based On Harmonic Superposition Method And Statistical Characteristics Of Wind Spectrum In Atmospheric Surface Flows

Harmonic superposition method is the most widely used approach in engineering for wind field reconstruction,which mainly generates wind speed fluctuation signals by constraining the different scale turbulent energies with target spectra and combining them with randomly assigned phase values.However,the random phase distributions ignore the close correlation between different scales of turbulence.Furthermore,the matrix decomposition and random phase superposition method used in the twodimensional wind field reconstruction process increases the complexity.This leads to the limitations of the method in reconstructing the quasi-ordered structures of wind field and the complexity of the algorithm.The author studied the multi-scale phase distribution of the wind field in atmospheric surface layer and fitted the law function of phase feature with height.The harmonic superposition method for wind field reconstruction is established which is based on phase characterization and a modified power spectral density function.The main results of this paper are as follows:Relying on field observation data in atmospheric surface layer,it is found that although the phase at a single height is approximately uniformly distributed,the phase difference or phase lag between different turbulence scales is scale-dependent at different heights.By dividing the physical spatial scale and analyzing the second-order statistics of the phase difference spectrum,this study revealed the variation law of phase lag spectrum with height and scale.Then a functional characterization of multiscale phase spectra with respect to the reference height is accomplished.Besides that,the bilinear characterization function of the power spectrum is improved and the parameters have been determined by analyzing experimental data,which makes the power spectrum more accurate for describing the characteristics of the "-1" spectral region.Finally,by establishing phase and power spectrum characterization,a two-dimensional wind field characterization model is constructed using the harmonic superposition method.The reliability of this model for wind field reconstruction and the efficiency of the algorithm are demonstrated by the comparison with the results in atmospheric surface layer.This paper provides a novel,easily applicable scheme for wind field reconstruction based on phase and power spectra of atmospheric surface layer wind field,which is helpful to improve the accuracy of the harmonic superposition method in realizing the structural features and coherent modes of wind fields.