Numerical Models for Predicting the Morphology of a Sand Island PDF Download

Author: K. Bruce Dean
Publisher:
ISBN:
Category :
Languages : en
Pages :

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Author: K. Bruce Dean
Publisher: National Library of Canada
ISBN:
Category :
Languages : en
Pages : 183

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Author: Wade H. Shafer
Publisher: Springer Science & Business Media
ISBN: 1461573912
Category : Science
Languages : en
Pages : 386

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Masters Theses in the Pure and Applied Sciences was first conceived, published, and disseminated by the Center for Information and Numerical Data Analysis and Synthesis (CINDAS) * at Purdue University in 1957, starting its coverage of theses with the academic year 1955. Beginning with Volume 13, the printing and dissemination phases of the activity were transferred to University Microfilms/Xerox of Ann Arbor, Michigan, with the thougtit that such an arrangement would be more beneficial to the academic and general scientific and technical community. After five years of this joint undertaking we had concluded that it was in the interest of all con cerned if the printing and distribution of the volumes were handled by an interna tional publishing house to assure improved service and broader dissemination. Hence, starting with Volume 18, Masters Theses in the Pure and Applied Sciences has been disseminated on a worldwide basis by Plenum Publishing Cor poration of New York, and in the same year the coverage was broadened to include Canadian universities. All back issues can also be ordered from Plenum. We have reported in Volume 31 (thesis year 1986) a total of 11 ,480 theses titles trom 24 Canadian and 182 United States universities. We are sure that this broader base tor these titles reported will greatly enhance the value ot this important annual reterence work. While Volume 31 reports theses submitted in 1986, on occasion, certain univer sities do re port theses submitted in previousyears but not reported at the time.

Author: Paul Michael Carroll
Publisher:
ISBN:
Category :
Languages : en
Pages : 86

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Keywords: morphology, coastal engineering, erosion, beach change.

Author: Florian Georges Albert Brehin
Publisher:
ISBN:
Category :
Languages : en
Pages : 390

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Sebastian Inlet is one of the four tidal inlets of the central Florida barrier island system that separates the Indian River Lagoon (IRL) from the Atlantic Ocean. The inlet channel was artificially cut into the limestone and the inlet was stabilized by offset jetties from the 1950's to the 1970's. The inlet is characterized by a substantial shoal system that developed as a response to the changed hydrodynamics, a narrow throat cross-sectional area, and a sand trap located at the westward edge of the channel that was first excavated in 1962 for mechanical bypassing to the downdrift beaches. Over the past 10 years more than 1 million cubic meters of sand have been placed on the beaches just to the south of the inlet to combat erosion. One of the challenges in sediment management is to reduce the cost of beach fills, which requires either finding new sand sources in proximity to the system or modifying the structural configuration of the inlet in order to lower the costs of the 70,000 m3 of sand that has to be bypassed annually to counteract downdrift erosion. Numerical simulations of the coupled circulation and wave models from the Coastal Modeling System (CMS) were performed to reproduce the hydrodynamics, sediment transport and morphological changes in the Sebastian Inlet area. The wave model (CMS-Wave) was forced using time series of wave parameters. The circulation model (CMS-Flow) was forced using time series of water levels and wind data along with forcing from the wave model. Model validations were carried out over a one year period from January to December 2011, separated into 6 months runs to match the available hydrographic survey dates. Simulations were performed with the Non Equilibrium Transport (NET) Lund sediment transport formula using variable sand grain size data from a recent sediment survey. Non-erodible cells representing reef rock outcrops were selected within the model domain. Model applications were focused on: (1) understanding the inlet and nearby beaches hydrodynamics and morphological response to coastal forcing over multiple time scales; (2) determining model performance in reproducing hydrodynamics and bottom topography changes over relatively long time scales (6 months), and (3) assessing the morphological changes associated with three hypothetical cases of engineering modifications to the inlet system including a south jetty extension, a sand trap excavation, and mining of the ebb shoal. The model showed good performance over the validation period. Model skills for the wave predictions ranged from 0.88 to 0.93 with Root Mean Square Error's (RMSE) of 0.22 and 0.29 for the January to June (winter) and July to December (summer) 2011 model runs, respectively. For the circulation model, RMSE's ranged from 0.21 to 0.19 at the ADCP location with model skills of 0.94 and 0.95 for the winter and summer validation time periods, respectively. Model performance was also highlighted in the results of current velocities with model skills of 0.64 and 0.67 and RMSE's of 0.06 and 0.05 for the January to June 2022 and June to December 2011 runs, respectively. Model results highlighted the variability in the current speed distribution, with stronger velocity in the inlet channel (2.5 m/s) during flood tide and a strong decrease in the back bay (0.25 m/s). The model successfully simulated typical stabilized inlet hydrodynamic features such as the ebb jet, current asymmetry and complex circulation near shoals. A strong linear correlation was reproduced between water levels and current for the stations in the inlet channel. Model outputs showed spatial and temporal variability in wave propagation as well, and emphasized the ebb shoal influence on reducing wave energy reaching the beaches from the south jetty to R2. Morphological model simulation outputs after each 6 months run showed good agreement with measured data. The model reproduced the main inlet evolution processes such as natural sand bypassing to the south, fluxes between deltas, and scouring in the inlet channel. The analysis of bottom topography profile changes showed that the best match occurred for the south beach domain. The model was able to reproduce sediment transport processes on beaches and the simulations underlined the complex interactions occurring in the south domain due to inlet/ebb shoal interactions and the presence of hard bottom through nearshore reef outcrops. Further, the model was successful in reproducing seasonal variation in sedimentation on the shoreface. The model failed to reproduce some of the patterns in the inlet channel and ebb shoal due to hard bottom cell control. Changes in volumes showed more variability, but most were in agreement for the smaller sand reservoirs. Even if trends were captured, there was a tendency for the model to overestimate changes on ebb shoal reservoirs. Results of the modeled hypothetical modifications showed that the south jetty extension case had mostly local impacts on the sedimentation and did not provide any significant sand trapping besides behind the jetty. Despite the possibility that ebb shoal mining would provide an easy access source of sand, modeled simulations showed this alternative would likely increase erosion over the longer term on the downdrift beaches due to sand accumulating in the borrow cut. This alternative would also deteriorate surfing waves quality on the ebb shoal of the inlet. Simulations for the sand trap excavation showed this alternative was likely to increase deposition by up to 2 m, therefore, increasing sand availability for mechanical bypassing to the downdrift beaches. The sand trap excavation scenario was chosen and the project was completed in Fall 2013.

Author:
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ISBN:
Category :
Languages : en
Pages :

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Numerical modeling in the nearshore region has become an important tool in both planning and design for coastal engineers. In recent decades, the complexity of these models has increased as our knowledge of existing processes has matured. However, gaps still remain between what we as engineers understand about the nearshore environment and what actually exists. Due to these uncertainties, modelers have taken different approaches to simulate sediment transport. The objective of this thesis is to evaluate the ability of two cross-shore numerical models, SBEACH and COSMOS, in their ability to predict subaerial beach profile change resulting from storm events. The predicted profiles from each model were compared to actual measured post-storm profiles. Quantitative comparison of results from both models was preformed using BMAP (Beach Morphology Analysis Package). A rating of good, fair, or poor was assigned to the models based on how closely each predicted the measured subaerial profile change. The waterline recession was also analyzed and a rating of reasonable or unreasonable was assigned to each model based on its predicted value. The fundamental difference between the two models is in regards to sediment transport. The SBEACH model predicts sediment transport rates as a function of wave energy dissipation. The COSMOS model utilizes the energetics approach where sediment transport is dependent on mean velocity currents in both the bed and the suspended boundary layers. The results presented within this report show that SBEACH performed equally as well or better in each case. The COSMOS model consistently over predicted erosion on the beach face and recession of the waterline. For the study sites where data was collected for this research, SBEACH is the recommended model by the author.

Author:
Publisher:
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Category :
Languages : en
Pages : 0

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Engineering structures and activities interfere with the sediment transport and morphological evolution in the coastal zone. Thus, it is necessary to understand, quantify, and predict the behavior of the morphology and how it interacts with such structures and activities when carrying out engineering projects on the coast (e.g., ports). The first step towards assessing the effects of engineering works on coastal morphology is to characterize the morphology itself and the mechanisms that control its evolution. Describing the morphology involves mean properties and trends as well as parameters quantifying a wide range of features that occur at many scales. The equilibrium shape of the beach profile or the shoreline, for a given configuration are typical examples of mean properties used to characterize the morphology, especially in engineering investigations. Morphological features in the coastal zone range from ripples to barrier islands, although it is typically only the feature at the scale of the project that has a potential for interaction with the engineering works and that needs to be studied. Here, the objective is to provide a brief overview of recent research in coastal morphology with the emphasis on quantifying the morphology of sandy beaches and its evolution. Most of the discussion is in the context of modeling, analytical or numerical, since engineering studies typically imply predictions about the future evolution of a particular coastal area and models are key tools in such studies.

Author: Jane Mckee Smith
Publisher: World Scientific
ISBN: 9814480525
Category : Science
Languages : en
Pages : 4836

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This comprehensive and up-to-date volume contains 367 papers presented at the 29th International Conference on Coastal Engineering, held in Lisbon, Portugal, 19-24 September 2004. It is divided into five parts: waves; long waves, nearshore currents, and swash; sediment transport and morphology; coastal management, beach nourishment, and dredging; coastal structures. The contributions cover a broad range of topics including theory, numerical and physical modeling, field measurements, case studies, design, and management. Coastal Engineering 2004 provides engineers, scientists, and planners state-of-the-art information on coastal engineering and coastal processes.The proceedings have been selected for coverage in:

Author:
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ISBN:
Category : Canada
Languages : en
Pages : 684

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Author: Michael Z. Li
Publisher: John Wiley & Sons
ISBN: 144435082X
Category : Science
Languages : en
Pages : 442

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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.