Final Stages of Wake Collapse in a Stratified Fluid
Final Stages of Wake Collapse in a Stratified Fluid

Author: Steven Weinberg

Publisher:

Published: 1973

Total Pages: 44

ISBN-13:

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Wake collapse in a stratified fluid is studied in the linear approximation with particular attention to the late stages of its decay. For an infinite ocean with a constant Vaisala frequency, any smooth disturbance will eventually decay as the minus three halves power of t. An apparent discrepancy between this result and the work of Hartman and Lewis is traced to the sharp discontinuity in their initial conditions. The normal modes for a realistic problem with an ocean surface and bottom and a varying Vaisala frequency are treated by methods developed in potential scattering theory, and the results are then used to estimate the behavior of the disturbance at late times.

Experiments on Turbulent Wakes in a Stable Density-stratified Environment
Experiments on Turbulent Wakes in a Stable Density-stratified Environment

Author: Walter P. M. van de Watering

Publisher:

Published: 1969

Total Pages: 74

ISBN-13:

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In a laboratory experiment, turbulent mixed regions were generated in a linearly density-stratified fluid and their behavior was studied. Such regions may occur in nature in the atmosphere and in the ocean. Particularly during their early history, the shape of such regions is influenced by the interacting effects of turbulence and buoyancy, culminating in the occurrence of a maximum thickness and subsequent vertical collapse. A Richardson number (equivalent to the ratio of the characteristic turbulence time and the Vaisala period) was found satisfactorily to correlate the data obtained, together with those previously obtained by other investigators with self-propelled bodies. An estimate is made of the degree of mixing that takes place inside a turbulent mixed region during its growth in stably-stratified surroundings: the effectiveness of this mixing determines the ultimate thickness to which the mixing region collapses. (Author).