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Publisher:
Published: 1992
Total Pages: 4
ISBN-13:
DOWNLOAD EBOOKOur research goals are to understand, quantify, and parameterize mixing processes in stably stratified fluids. The research is intended to provide a sound scientific basis for making accurate quantitative estimates of ocean mixing from limited observations at sea.
Author: J.C.J. Nihoul
Publisher: Elsevier
Published: 1988-05-01
Total Pages: 557
ISBN-13: 0080870848
DOWNLOAD EBOOKThis volume contains the proceedings of the 19th International Liège Colloquium on Ocean Hydrodynamics, the programme of which focused on the relationships between small-scale mixing and large-scale features, transports and processes. The presentation of papers on various methods of parameterization of small-scale turbulent mixing for numerical ocean models was particularly encouraged and this resulted in more than a third of the papers presented at the Colloquium dealing in one way or another with the parameterization problems; many of these papers demonstrate the direct results of modelling. These proportions are well reflected in this volume of proceedings and thus emphasize once more the importance of small-scale turbulence research for such vital practical applications as ocean modelling and forecasting.
Author: Michael Meredith
Publisher: Elsevier
Published: 2021-09-16
Total Pages: 386
ISBN-13: 0128215135
DOWNLOAD EBOOKOcean Mixing: Drivers, Mechanisms and Impacts presents a broad panorama of one of the most rapidly-developing areas of marine science. It highlights the state-of-the-art concerning knowledge of the causes of ocean mixing, and a perspective on the implications for ocean circulation, climate, biogeochemistry and the marine ecosystem. This edited volume places a particular emphasis on elucidating the key future questions relating to ocean mixing, and emerging ideas and activities to address them, including innovative technology developments and advances in methodology. Ocean Mixing is a key reference for those entering the field, and for those seeking a comprehensive overview of how the key current issues are being addressed and what the priorities for future research are. Each chapter is written by established leaders in ocean mixing research; the volume is thus suitable for those seeking specific detailed information on sub-topics, as well as those seeking a broad synopsis of current understanding. It provides useful ammunition for those pursuing funding for specific future research campaigns, by being an authoritative source concerning key scientific goals in the short, medium and long term. Additionally, the chapters contain bespoke and informative graphics that can be used in teaching and science communication to convey the complex concepts and phenomena in easily accessible ways. Presents a coherent overview of the state-of-the-art research concerning ocean mixing Provides an in-depth discussion of how ocean mixing impacts all scales of the planetary system Includes elucidation of the grand challenges in ocean mixing, and how they might be addressed
Author: Young Ro Yi
Publisher:
Published: 2023
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKGlobal and regional ocean simulations rely on eddy viscosities and diffusivities to represent the unresolved turbulent mixing of momentum and scalars. The simulated flow and the transport of quantities such as heat and carbon are quite sensitive to how the turbulence is modeled. Particularly, the eddy diffusivity model of Osborn (1980) is widely used to represent the vertical buoyancy flux, which requires accurate knowledge of the mixing coefficient--defined as the ratio of the dissipation rates of available turbulent potential energy (TPE) and turbulent kinetic energy (TKE). While a constant value of 0.2 is often prescribed for the mixing coefficient, there is significant evidence for parameterizing it as a function of dimensionless numbers that characterize the state of the turbulence. Using direct numerical simulations, we studied stably stratified turbulence under three different sets of forcing: (i) linear axisymmetric forcing; (ii) three types of shear forcing; and (iii) combined momentum and buoyancy forcing. By analyzing the budgets of the normal Reynolds stresses and the vertical buoyancy flux, we observed that terms involving the pressure field (i.e., pressure-strain correlations and pressure scrambling) exhibited significant changes as the turbulent mixing became more efficient. Each of these three sets of flows exhibited quantitative physical differences in their mixing characteristics. Our findings suggested the need for improved models of the turbulent mixing in stratified flows, which we achieved by revising existing scaling relationships for the mixing coefficient and exploring anisotropic model forms for the turbulent momentum and scalar fluxes.
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Publisher:
Published: 1995
Total Pages: 426
ISBN-13:
DOWNLOAD EBOOKAuthor: Hans Burchard
Publisher: Springer
Published: 2007-08-15
Total Pages: 224
ISBN-13: 3540454195
DOWNLOAD EBOOKThe simulation of turbulent mixing processes in marine waters is one of the most pressing tasks in oceanography. It is rendered difficult by the various complex phenomena occurring in these waters like strong stratification, ex ternal and internal waves, wind generated turbulence, Langmuir circulation etc. The need for simulation methods is especially great in this area because the physical processes cannot be investigated in the laboratory. Tradition ally, empirical bulk type models were used in oceanography, which, however, cannot account for many of the complex physical phenomena occurring. In engineering, statistical turbulence models describing locally the turbulence mixing processes were introduced in the early seventies, such as the k E model which is still one of the most widely used models in Computational Fluid Dy namics. Soon after, turbulence models were applied more and more also in the atmospheric sciences, and here the k kL model of Mellor and Yamada became particularly popular. In oceanography, statistical turbulence mod els were introduced rather late, i. e. in the eighties, and mainly models were taken over from the fields mentioned above, with some adjustments to the problems occurring in marine waters. In the literature on turbulence model applications to oceanography problems controversial findings and claims are reported about the various models, creating also an uncertainty on how well the models work in marine water problems.
Author:
Publisher:
Published: 1998
Total Pages: 0
ISBN-13:
DOWNLOAD EBOOKA comprehensive research program was carried out to investigate turbulence, waves and mixing in oceanic surface and benthic boundary layers, with special emphases on the generation, sustenance, diffusion and decay of turbulence in such layers. The research was mainly laboratory experimental supplemented by analytical and numerical developments. The penetration of a shear-generated turbulent layer into a stably stratified non-turbulent layer, with applications to the oceanic surface-layer deepening, was the theme of the first part of the research program; the rate of turbulent-layer propagation, energetics, diffusion of mass, momentum and turbulent kinetic energy and small scale processes were the studied in detail. The applicability of results to oceanic situations, especially for surface-layer modeling, was also evaluated. The second part of the investigation dealt with oscillatory, surface-wave boundary layers, mimicked in the laboratory by an oscillatory bed underlying either a quiescent fluid layer or a mean current. The aim was to measure the diffusivities of momentum, mass and turbulent kinetic energy in such layers and to use the results to verify commonly used parameterizations in predictive models for coastal oceans.
Author: P. A. Davies
Publisher: Oxford University Press
Published: 1999
Total Pages: 668
ISBN-13: 9780198500155
DOWNLOAD EBOOKStratified 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.
Author: Michael C. Gregg
Publisher: Cambridge University Press
Published: 2021-02-04
Total Pages: 385
ISBN-13: 1107173809
DOWNLOAD EBOOKThis book examines how large-scale processes drive centimetre-scale mixing throughout the stratified ocean. It explores the primary factors affecting mixing and turbulence, and reviews insights from laboratory studies and numerical modelling. It is an excellent reference for researchers and graduate students in oceanography and related fields.
Author: Jorg Imberger
Publisher: American Geophysical Union
Published: 1998
Total Pages: 678
ISBN-13: 0875902685
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