Mechanics Of Coastal Sediment Transport

Mechanics Of Coastal Sediment Transport

Author: Jorgen Fredsoe

Publisher: World Scientific Publishing Company

Published: 1992-11-02

Total Pages: 390

ISBN-13: 9814365688

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This book treats the subject of sediment transport in the marine environment, covering transport of noncohesive sediment by waves and currents in- and outside the surf zone. It can be read independently, but a background in hydraulics and basic wave mechanics is required.The primary aim of the book is to describe the physical processes of sediment transport and how to represent them in mathematical models. The book can be divided in two main parts; in the first, the relevant hydrodynamic theory is described. This part contains a review of elementary theory for water waves, chapters on the turbulent wave boundary layer and the turbulent interaction between waves and currents, and finally, surf zone hydrodynamics and wave driven currents.The second part covers sediment transport and morphological development.The part on sediment transport introduces the basic concepts (critical bed shear stress, bed load, suspended load and sheet layer, near-bed concentration, effect of sloping bed); it treats suspended sediment in waves and current and in the surf zone, and current and wave-generated bed forms. Finally, the modelling of cross-shore and long-shore sediment transport is described together with the development of coastal profiles and coastlines.


Suspended Sediments Measured in the Surf Zone

Suspended Sediments Measured in the Surf Zone

Author: William Denton Morris

Publisher:

Published: 1977

Total Pages: 108

ISBN-13:

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Suspended sediments were measured optically within the surf zone at Torrey Pines Beach, California. Sediment laden water was sampled through three intake nozzles which were mounted on a tower along with the optical sensor (nephelometer) which was in line with the sediment laden water which was pumped to the shore. The nephelometer gave a time series of the suspended sediments. The water pumped to the beach was filtered to obtain total sediment concentration. Horizontal velocities were measured simultaneously with an electromagnetic current meter mounted on the same tower. During the experiments the breaker height ranged between 1 and 2 meters and the mean period between 8 to 16 seconds. The peaks of the nephelometer spectra occurred at approximately twice the peak frequency in the velocity spectra indicating two or more maximas per wave period. Cross spectra were computed between suspended sediments and horizontal velocity. A maximum coherence ranging above .7 occurred at the first harmonic of the peak wave frequency. The suspended sand was well sorted quartz with a mean grain size of 0.15 mm. Suspended sand concentration appeared to decrease exponentially with height above the bottom with the rate of decrease and total concentration related to the mean bed shear stress. Mean sand concentration ranged between 0.05 to 0.32 grams of sand per liter of sea water. (Author).


Surf Zone Properties and On/offshore Sediment Transport

Surf Zone Properties and On/offshore Sediment Transport

Author: Wei-Chong Yang

Publisher:

Published: 1982

Total Pages: 232

ISBN-13:

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The surf zone properties and the on/offshore sediment transport rate were studied. A non-dimensional surf zone parameter was obtained by taking the ratio of natural swash period to wave period. This parameter, in addition to its wide application in describing the breaker types, was pertinent to describing the flow patterns in surf zone and defining the region of validity of the similarity solutions. A similarity model was applied to describe the flow field of breaking waves in surf zone. Laboratory results from other investigators and those obtained in the present study were used to test the validity of the proposed model. (Author).


Suspended Sediment in Breaking Waves

Suspended Sediment in Breaking Waves

Author: Timothy W. Kana

Publisher:

Published: 1979

Total Pages: 174

ISBN-13:

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Suspended sediment concentration was measured in 235 breaking waves on undeveloped beaches near Price Inlet, South Carolina, U.S.A., using portable in situ bulk water samplers. The purpose of the study was to determine what factors control the distribution of suspended sediment in the breaker zone. The final conclusion inferred from accumulated data is that sediment transport is highly dependent on breaker type. Net offshore movement and equilibrium profiles can be qualitatively explained on the basis of variations in wave form, beach slope and suspended sediment concentration. Longshore transport rates are dependent not only on wave height, but on breaker type, which can be quantified to reasonable certainty by the simple ratio, d sub b/H sub b, relative wave height. (Author).


Nearshore Sediment Transport

Nearshore Sediment Transport

Author: R.J. Seymour

Publisher: Springer Science & Business Media

Published: 2013-11-11

Total Pages: 410

ISBN-13: 1489925317

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This book represents the efforts of over a hundred individuals who planned and executed the NSTS field experiments, analyzed the billions of data points, and distilled their findings and insights into the summaries found here. Because these experiments were of a scope that will seldom, if ever, be duplicated, and because the program brought together many of the foremost field experimentalists in this country, we all felt from the beginning that it was important to preserve the outcome. This was done in two ways. First, the raw data were made available to any interested investigator within 18 months of the completion of each experiment. Secondly, both the methodology of the experiments and the findings from them were codified in the form of a monograph. This book is that result. I have had the occasion recently (Sediments '87 Proceedings, Vol. 1, pp. 642-651) to assess the NSTS performance. I found that we made giant strides in our understanding of the surf zone hydrodynamics --far more than our fondest expectations at the beginning. We were able to do less than we had hoped about the response of the sediment, largely because of a limited ability to measure it at a point. As I reported in the Sediments '87 assessment, we established a new state of the art in measurement techniques and we demonstrated the effectiveness of large, multi-investigator, instrument-intensive experiments for studying nearshore processes.