Prediction of Hydrodynamic Pressure Bottom Noise With Moderate Waves in Coastal Waters

Abstract

The present article aims at estimation of creating a mathematical model for urgent predicting the parameters of a bottom hydrodynamic pressure noise in coastal waters in depending on the spectrum of moderate surface waves. The proportions of estimating hydrodynamic pressure spectra, as a result of turbulence in dependence on its spectral composition are given. It is shown that average pressure spectra is close to «−2» power law and at the absence of significant surface waves pressure spectrum noise is corresponding to the turbulence with the dissipation rate ε ≈ 10-⁶–10-⁵ m²⁄s³. For the moderate surface waves conditions regression of turbulent pressure level dependence of the wave spectrum peak magnitude and frequency have been obtained. Regression of low-frequency level of the spectrum wave dependence of the wave spectrum peak magnitude has also been obtained. The data of the low-frequency level of the part of the surface wave spectrum don’t contradict to the Firsov—Rakhmanin model. The mathematical model of hydrodynamic bottom pressure spectra depending on the parameters of the wave spectrum and estimation of model coefficients are proposed. The model takes into account turbulence noise, low-frequency wave noise and «area of the maximum» wave noise. The average difference between predicted and experimental values for the full sample of data is close to 4 dB. Identification of variability of model coefficients under different hydrophysical conditions requires further systematic agreed measurements of surface waves and bottom pressure noise in water areas of practical interest.