At present,a variety of algorithms have been used to measure the flow velocity of backward-facing step turbulent media,but most of them have the problems of low repeatability and poor robustness.Therefore,a velocity measurement method of line array sensors based on wavenumber-frequency spectrum analysis is proposed.Firstly,the turbulence degree and Taylor freeze signal characteristics of the backward-facing step data are analyzed.Secondly,FDBM and MUSIC algorithms are used to convert sensors data from the x-t domain to the k-ω domain,showing the characteristic"ridge line"related to the backward-facing step velocity.Then,the influence of different beam forming filtering algorithms and power spectrum block length on velocity"ridge"is explored.Finally,wavenumber-frequency spectrum is used to analyze the slope of ridge line to solve the velocity.Compared with the traditional cross-correlation method,the relative error is 2.83%and the repeatability is 0.32%.The results show that the wave-frequency spectrum method can effectively measure the backward-facing step flow velocity,has good repeatability and robustness.
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