Accession Number : AD0665765

Title :   WAKE COLLAPSE AND SUBSEQUENT GENERATION OF INTERNAL WAVES IN A DENSITY STRATIFIED MEDIUM.

Descriptive Note : Technical rept.,

Corporate Author : HYDRONAUTICS INC LAUREL MD

Personal Author(s) : Wu,Jin

Report Date : JAN 1968

Pagination or Media Count : 51

Abstract : An experimental technique was developed to model a two-dimensional mixed region collapsing in a continuously density-stratified medium. The process of this mixed region can be divided into three stages. Empirical formulae were derived to describe the process of the first two stages, during which densimetric effects determine the modeling criterion. The collapse process in the final stage is complicated by viscous effects including mixing at the thin wake tip. The pattern of the internal waves generated by the initial impulsive collapse of the mixed region was studied; it can be represented by moving rays connecting either wave crests or troughs. These rays move away from the collapse center and at the same time decrease their slopes. A simpler steady state wave pattern generated by an oscillating plunger was also studied. Taken together, these experimental results are interpreted to show that the energy density of the initial impulsive collapse is skewed toward higher frequencies and that it is peaked at 8/10 of the Brunt-Vaisala frequency. The mechanism underlying the moving ray patterns is explained. (Author)

Descriptors :   (*MARINE SURFACE PROPULSION, WAKE), (*OCEAN MODELS, HYDRODYNAMICS), ATTENUATION, LAMINAR FLOW, DENSITY, OCEAN WAVES, LINEAR SYSTEMS, DIFFUSION, FREQUENCY, PROPAGATION

Subject Categories : Marine Engineering
      Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE