A Theory of Mixing in a Stably Stratified Fluid
A Theory of Mixing in a Stably Stratified Fluid

Author: Robert R. Long

Publisher:

Published: 1977

Total Pages: 23

ISBN-13:

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A theory is developed for turbulence in a stably stratified fluid. A growing mixed layer of thickness D appears in the lower portion of the fluid, separated from the non-turbulent fluid above, in which the mean buoyancy gradient is given, by an interfacial layer (IL) of thickness h. When there is stratification, the fluid motion is unaffected by buoyancy forces in the mixed layer. If the upper fluid is of uniform buoyancy, D delta b = v squared may be shown to be constant if we accept the experimental observation that h is proportional to D. In general v may be taken to be a fundamental parameter expressing the stability. The quantity Ri = (v d/k) squared is the most fundamental of the several Richardson numbers that have been introduced in this problem because, with its use, constants of proportionality do not depend on the molecular coefficients of viscosity or diffusion (for high Reynolds number turbulence) or on the geometry of the grid.

Collapse of Partially Mixed Regions in Stratified Fluids
Collapse of Partially Mixed Regions in Stratified Fluids

Author: J. P. Dugan

Publisher:

Published: 1974

Total Pages: 20

ISBN-13:

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The collapse of a partially mixed fluid mass immersed in a stably stratified fluid is studied with a finite difference formulation of the Navier-stokes equations. In a series of tests, the mixed region is assumed to have various types of density structure including ones derived from both uniform and nonuniform amounts of mixing. The shape of the mixed region is followed in detail. The temporal history of the width of the mixed region agrees with a simple analytical model in the initial stage of collapse in the case where the amount of mixing is uniform. It also compares well with a previous analytical theory in the case of a small amount of mixing where that theory is valid. Most of the energy stored in the mixed region is given up to the surrounding fluid in one Brunt-Vaisala period. (Author).

Mixing and Dispersion in Stably Stratified Flows
Mixing and Dispersion in Stably Stratified Flows

Author: P. A. Davies

Publisher: Oxford University Press

Published: 1999

Total Pages: 668

ISBN-13: 9780198500155

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Stratified flows are important in determining how various atmospheric and environmental processes occur. The book investigates these processes and focuses on the methods by which pollutants are mixed and dispersed in natural and industrial environments.

Stratified Flows
Stratified Flows

Author: Chia-Shun Yih

Publisher: Elsevier

Published: 2012-12-02

Total Pages: 439

ISBN-13: 0323150403

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Stratified Flows is the second edition of the book Dynamics of Nonhomogenous Fluids. This book discusses the flow of a fluid of variable density or entropy in a gravitational field. In this edition, corrections have been made; unnecessary parts have been omitted; and new sections as well as notes on results related to the subject have been added. This book includes a general discussion of the effects of density or entropy and the structure of stratified flows; waves of small amplitude; the Eigenvalue problem; dependence of phase velocity on wavelength; wave motion; steady flows of finite amplitude; and types of solutions for steady flows. This edition also covers other topics such as hydrodynamic stability; flows in porous media; and the analogy between gravitational and electromagnetic forces. This text is recommended for those in the field of physics who would like to be familiarized with stratified flows and its related concepts.

Lectures on Turbulence and Mixing Processes in Stratified Fluids
Lectures on Turbulence and Mixing Processes in Stratified Fluids

Author: Robert R. Long

Publisher:

Published: 1974

Total Pages: 141

ISBN-13:

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The report contains a set of notes based on a set of lectures for a summer course 'Vertical Exchange Processes in the Sea'. Topic 1 gives a background discussion of basic fluid mechanical problems and simple turbulence theory. Topic 2 discusses mixing in a stably stratified fluid. Topic 3 is concerned with the Richardson number, the flux Richardson number and eddy coefficients of viscosity and buoyancy together with a discussion of mass and salt transfers at the mouth of an estuary and a determination of the depth of the halocline in an estuary. Topic 4 contains a discussion of the surface layer of the atmosphere. Topic 5 discusses density currents and wake collapse. Topic 6 involves problems in which the earth's rotation is important. (Author).