ИСТИНА

Abstract: Transverse flow of inhomogeneous current produces fluctuation of the acoustic signal passing through it. These fluctuations vary with the CW signal frequency change due to variation of the Fresnel zone size. Respectively, the fluctuations of amplitude and phase of frequency-spaced acoustical signals are coherent at the low frequency and no coherent at the high-frequency band of fluctuations. The frequency cutoff of the coherence function depends upon the flow velocity at given fine structure of the turbulent flow. The measurement of the cutoff frequency allows determining the transverse current velocity. This method can be considered as a frequency-domain version of the conventional scintillation approach to the current velocity. It efficiency was verified earlier at the example of tidal current retrieval for the field research at Cordova Channel (Canada). Now we present here results of the experimental research of multi-frequency acoustical technique implementation to retrieve both the flow velocity and the spatial position of the transversal turbulent stream in a quiet environment. Besides the results of experimental research the paper presents a brief theory review of the method both and computer simulation of multi-frequency signal propagation through the variable inhomogeneous medium. Hereby prospective multi-frequency acoustical technology for ocean observatory is discussed.