Phase structure of three-dimensional internal waves in a channel

Abstract

The results of a theoretical and experimental investigation of the phase structure of three-dimensional internal waves in a horizontal channel occupied by an exponentially stratified fluid are presented. The stationary internal waves excited by a source moving uniformly along the bottom of a channel with rigid covers are considered. A dispersion relation, on the basis of which the phase structure of the internal waves in the far zone is investigated, is obtained within the context of the linear theory. The dependence of the boundary of the region of wave disturbances on the internal Froude number F is found. The equation of the lines of constant phase is obtained in the first approximation for large F. By means of an IAB-451 shadowgraph instrument, using the dark field method with vertical illumination, the phase patterns of the internal waves are obtained. The angles of the wave disturbance zone are measured in the region of relatively large F. Similarity of the phase patterns for the first three-dimensional mode is obtained experimentally for large F.