Accession Number : AD0668185

Title :   LONG WAVES OVER WAVY BOTTOMS.

Descriptive Note : Technical rept.,

Corporate Author : CHICAGO UNIV ILL DEPT OF THE GEOPHYSICAL SCIENCES

Personal Author(s) : McGoldrick,L. F.

Report Date : JAN 1968

Pagination or Media Count : 69

Abstract : The propagation of long waves over bottoms having sinusoidal undulations is investigated here within the confines of linearized shallow water theory. It is found that the presence of this irregularity in most cases impedes the propagation of the wave in keeping with the proper application of the Green-DuBoys formula. For wavelengths for which this formula is not valid, or those of the same order as the bottom wavelengths, it is found that there is a region for which the propagation is not retarded, and the travel time is less than that based upon the mean depth. Furthermore, the presence of regular undulations of the bottom of any amplitude prohibits the propagation of an infinite sequence of wavelengths on the surface, the most significant of which are those of the same order as the bottom. These waves are unstable, and through resonance with the bottom will grow without bound as they progress, or at least until the linearized theory is invalidated. An electrical analog is presented which exhibits the same instability, a subharmonic resonance, and can be used to determine the free surface profiles. (Author)

Descriptors :   (*OCEAN WAVES, PROPAGATION), SHALLOW WATER, THEORY, STABILITY, WATER WAVES, OCEAN BOTTOM, VELOCITY, OCEAN BOTTOM TOPOGRAPHY, SURFACE PROPERTIES, MATHEMATICAL ANALYSIS, ANALOG SYSTEMS, ELECTRICAL PROPERTIES, TABLES(DATA)

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE