Coastal Bottom Boundary Layers And Sediment Transport

Coastal Bottom Boundary Layers And Sediment Transport
Author: Peter Nielsen
Publisher: World Scientific Publishing Company
Total Pages: 340
Release: 1992-07-21
Genre: Technology & Engineering
ISBN: 9813103582

This book is intended as a useful handbook for professionals and researchers in the areas of Physical Oceanography, Marine Geology, Coastal Geomorphology and Coastal Engineering and as a text for graduate students in these fields. With its emphasis on boundary layer flow and basic sediment transport modelling, it is meant to help fill the gap between general hydrodynamic texts and descriptive texts on marine and coastal sedimentary processes. The book commences with a review of coastal bottom boundary layer flows including the boundary layer interaction between waves and steady currents. The concept of eddy viscosity for these flows is discussed in depth because of its relation to sediment diffusivity. The quasi-steady processes of sediment transport over flat beds are discussed. Small scale coastal bedforms and the corresponding hydraulic roughness are described. The motion of suspended sand particles is studied in detail with emphasis on the possible suspension maintaining mechanisms in coastal flows. Sediment pickup functions are provided for unsteady flows. A new combined convection-diffusion model is provided for suspended sediment distributions. Different methods of sediment transport model building are presented together with some classical models.

Modelling and Analysis of Fine Sediment Transport in Wave-Current Bottom Boundary Layer

Modelling and Analysis of Fine Sediment Transport in Wave-Current Bottom Boundary Layer
Author: Liqin Zuo
Publisher: CRC Press
Total Pages: 193
Release: 2018-06-19
Genre: Science
ISBN: 0429794029

The evolution and utilization of estuarine and coastal regions are greatly restricted by sediment problems. This thesis aims to better understand fine sediment transport under combined action of waves and currents, especially in the wave-current bottom boundary layer (BBL). Field observations, experimental data analysis, theoretical analysis and numerical models are employed. Silt-dominated sediments are sensitive to flow dynamics and the suspended sediment concentration (SSC) increase rapidly under strong flow dynamics. This research unveils several fundamental aspects of silty sediment, i.e., the criterion of the incipient motion, the SSC profiles and their phase-averaged parameterization in wave-dominated conditions. An expression for sediment incipient motion is proposed for silt-sand sediment under combined wave and current conditions. A process based intra-wave 1DV model for flow-sediment dynamics near the bed is developed in combined wave-current conditions. The high concentration layer (HCL) was simulated and sensitivity analysis was carried out by the 1DV model on factors that impact the SSC in the HCL. Finally, based on the 1DV model, the formulations of the mean SSC profile of silt-sand sediments in wave conditions were proposed. The developed approaches are expected to be applied in engineering practice and further simulation.

Coastal Bottom Boundary Layers and Sediment Transport

Coastal Bottom Boundary Layers and Sediment Transport
Author: Peter Nielsen
Publisher: World Scientific
Total Pages: 356
Release: 1992
Genre: Science
ISBN: 9789810204730

This book is intended as a useful handbook for professionals and researchers in the areas of Physical Oceanography, Marine Geology, Coastal Geomorphology and Coastal Engineering and as a text for graduate students in these fields. With its emphasis on boundary layer flow and basic sediment transport modelling, it is meant to help fill the gap between general hydrodynamic texts and descriptive texts on marine and coastal sedimentary processes. The book commences with a review of coastal bottom boundary layer flows including the boundary layer interaction between waves and steady currents. The concept of eddy viscosity for these flows is discussed in depth because of its relation to sediment diffusivity. The quasi-steady processes of sediment transport over flat beds are discussed. Small scale coastal bedforms and the corresponding hydraulic roughness are described. The motion of suspended sand particles is studied in detail with emphasis on the possible suspension maintaining mechanisms in coastal flows. Sediment pickup functions are provided for unsteady flows. A new combined convection-diffusion model is provided for suspended sediment distributions. Different methods of sediment transport model building are presented together with some classical models.

A General Formula for Noncohesive Suspended Sediment Transport

A General Formula for Noncohesive Suspended Sediment Transport
Author:
Publisher:
Total Pages: 14
Release: 2008
Genre:
ISBN:

A simple and robust suspended load transport formula for noncohesive sediment is presented for application to river, estuarine, and coastal environments with the use of depth-averaged models. The formula is based on an exponential profile for the concentration and assumes a constant velocity over depth to simplify the calculations. These assumptions were validated with a large data set, including data with a steady current, wave and current interaction, and breaking waves. The formula has two parameters: the mean sediment diffusivity over depth and the bottom reference concentration. The sediment diffusivity is estimated assuming a linear combination of mixing because of breaking waves and the energy dissipation in the bottom boundary layer from the mean current, waves, or both. The bottom reference concentration is a function of the Shields parameter. Overall, the formula developed in this study yields the best agreement with the compiled data set compared with a number of existing formulas for estimating the suspended load.

Data Report: Stress Measurements in the Bottom Boundary Layer with BASS Tripods STRESS II 1990-1991

Data Report: Stress Measurements in the Bottom Boundary Layer with BASS Tripods STRESS II 1990-1991
Author:
Publisher:
Total Pages: 44
Release: 1993
Genre:
ISBN:

Two Benthic Acoustic Stress Sensor (BASS) equipped tripods were deployed in the Sediment TRan5port Events on Shelves and Slopes (STRESS) experiment on the California Shelf acquiring data from January to March 1991. They measured velocity profiles in the bottom boundary layer over the lowest 5 meters. Transmissometers, thermistors, and a pressure sensor on each tripod provided suspended sediment concentration, stratification, and wave spectral information, as well. Benthic boundary layer, Sediment transport, Boundary layer stress.

Sediment Transport Mechanisms In Coastal Environments And Rivers - Euromech 310

Sediment Transport Mechanisms In Coastal Environments And Rivers - Euromech 310
Author: John F A Sleath
Publisher: World Scientific
Total Pages: 434
Release: 1994-12-08
Genre:
ISBN: 9814550523

These proceedings contain papers by some of the world's leading experts in the analytical and numerical modelling of sediment transport, its measurement on site and in the laboratory, river and coastal morphology, and similar issues. These topics are of fundamental importance in many areas (such as the silting or erosion of coasts and rivers, and the design of fluvial or coastal structures) and should consequently be of interest to a wide audience in engineering, geology and related disciplines.

Sediments, Morphology and Sedimentary Processes on Continental Shelves

Sediments, Morphology and Sedimentary Processes on Continental Shelves
Author: Michael Z. Li
Publisher: John Wiley & Sons
Total Pages: 442
Release: 2012-02-20
Genre: Science
ISBN: 144435082X

The application of multibeam and sediment transport measurement technologies and the adoption of multi-faceted research methodologies have greatly advanced our understanding of the sedimentary processes on continental shelves in the last decade. This book uniquely blends cutting-edge research and state-of-the art review articles that take stock of new advances in multibeam mapping and sediment transport technologies, spatial analysis and modelling, and the applications of these advances to the understanding of shelf sediments, morphodynamics, and sedimentary processes. Case studies are also presented to illustrate the utilization of seabed property and process knowledge in habitat mapping and ocean management With its mix of papers focusing on technological advances, integration of shelf morphology and processes, and the application of these advances to coastal and ocean management, this Special Publication volume will serve as a milestone reference for professional marine scientists and as advanced text for students in marine geology, sedimentology and oceanography. This book is part of the International Association of Sedimentologists (IAS) Special Publications. The Special Publications from the IAS are a set of thematic volumes edited by specialists on subjects of central interest to sedimentologists. Papers are reviewed and printed to the same high standards as those published in the journal Sedimentology and several of these volumes have become standard works of reference.