Damping of surface waves due to turbulence in application to the problem of ocean remote sensing

摘要

Understanding of physical mechanisms of gravity capillary waves (GCW) damping due to an impact of turbulence isimportant for developing methods of ship wake remote sensing, especially for tracking and characterization of ships.Analysis of literature reveals the necessity of setting a reliable experiment to study the effect of damping of GCW due toturbulence. Available laboratory studies are based on significantly different experimental methods with somedisadvantages which have caused a large scatter of experimental data. The previously proposed method, which is basedon the simultaneous independent generation of surface waves and turbulence in a wave tank, is free from inherentdisadvantages of previously used methods. The method is used to conduct a series of experiments in order to measure thedependence of the damping coefficient of GCW on their frequency at different intensities of turbulence in a widefrequency range. Due to the proposed technique the range of surface wavelengths is extended in order to investigate thecase when the surface wavelength is comparable to the scale of turbulence. It is shown that the frequency dependence ofthe eddy viscosity coefficient is characterized by the presence of a maximum for both turbulent regimes. The maximumvalue of eddy viscosity coefficient is proportional to the velocity of turbulent pulsations. The results are discussed inapplication to radar imaging of turbulent ship wake.