
Accession Number : AD0712442
Title : INTERNAL WAVES PRODUCED BY SPHERES MOVING IN DENSITY STRATIFIED WATER,
Corporate Author : NATIONAL BUREAU OF STANDARDS WASHINGTON D C
Personal Author(s) : Lofquist,Karl
Report Date : 1970
Pagination or Media Count : 61
Abstract : The report contains experimental observations and a theoretical study of the lee waves behind a sphere moving with constant horizontal velocity through a stably stratified liquid. The density decrease with height is nearly linear in the region of sensible waves. The observations were made in a tank of stratified salt water. In dimensionless plots, the vertical displacement is given as function of position behind the sphere and of the sphere's size and speed. Over much of their range, the displacements were noticeably affected by the horizontal boundaries of the stratified region, which were non rigid interfaces. The theory is approximate and applies only to the case of an unbounded fluid. However, it does not require the assumption of a low profile disturbance and also avoids anomalies found to be associated with a doublet disturbance. The nature of the disturbance and its effect upon the waves are embodied in a function, G, contained in the solution, which includes the doublet model as a special case. This function cannot exactly satisfy, nor be determined by, the condition of no flow through the surface of the sphere. However, a suitable form of G is derived empirically from a part of the observations. The region of direct comparability between observations and theory is limited by the disparity in their outer boundary conditions. As far as comparison can be extended, the observations and theory are reasonably compatible. (Author)
Descriptors : (*WATER WAVES, SPHERES), DENSITY, VELOCITY, MATHEMATICAL ANALYSIS
Subject Categories : Fluid Mechanics
Distribution Statement : APPROVED FOR PUBLIC RELEASE