Calculation of Phase Velocities in the Field of Sea Surface Waves

Abstract

Specific features of phase velocities of sea waves due to the angular distribution of wave energy and the second harmonic of a dominant wave with a velocity differing from the phase velocity of a free wave at the same frequency have been analyzed. The presence of wave components with different velocity projections on a given direction or different propagation velocities leads to a deviation in the estimates of phase velocities from the values resulting from a variance relationship for gravitational waves in deep water. It has been shown that the phase spectrum in field of sea waves varies nonlinearly with increasing distance between the relevant points. As a consequence, the estimates for phase velocity are functions of distance. The deviations of the estimates for phase velocity from the linear theory have been shown to depend on the stage of wave field development.