Download or read book Vertical Profiles of Longshore Currents written by Carlos Manuel da Costa Ventura Soares and published by . This book was released on 1995 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Topics in Longshore Currents written by John Casey Church and published by . This book was released on 1993 with total page 140 pages. Available in PDF, EPUB and Kindle. Book excerpt: The momentum equation governing mean longshore currents on straight beaches is a balance of forcing from the momentum transfer of the oscillatory wave motion, turbulent momentum transfer (mixing), and bottom stress. Of these, the wave's contribution is well understood, but the remaining two are not, principally due to the complicated hydrodynamics of the surf-zone. Addressing the bottom stress term, a longshore current model is developed which includes a modification of the bottom stress due to the effects of breaking-wave induced turbulence. A one-dimensional turbulent kinetic energy equation is used to model this breaking-wave induced turbulence, producing a spatially varying bottom friction coefficient. The modeled longshore current cross-shore profiles show improved agreement with field observations. In a second bottom stress study, vertical profiles of mean longshore currents are examined using field data obtained with vertically stacked electromagnetic current meters with the goal of measuring the bottom stress and its associated drag coefficient. The profiles are observed to become vertically uniform whenever the ratio of wave height to depth exceeds 0.3, indicating that nearly all of the waves passing a given location are breaking. Finally, horizontal turbulent momentum transfer (mixing) is examined for the case of shear instabilities of the longshore current.

Download or read book A Simple Quasi three Dimensional Model of Longshore Currents Over Arbitrary Profile written by Antonio Fernando Garcez Faria and published by . This book was released on 1995 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: The long shore current maximum observed in the trough of a barred beach during the nearshore dynamics experiment DELILAH at Duck, North Carolina, is not predicted by present theory. The simplest longshore curren models balance cross-shore changes in the alongshore wave momentum (radiation stress) with the alongshore bottom shear stress. Waves break over the bar, reform in the trough and again break on the foreshore resulting in changes in the radiation stress, which predicts two jets, one over the bar and the other at the foreshore, which does not agree with the observed current maximum in the trough. The advection of the momentum of the longshore current by mean cross-shore currents as a source of momentum mixing is investigated. The longshore current is strongest toward the surface and decreasing to zero at the bottom. The cross-shore mean current has an onshore transport in the wave crest/trough region and an offshore transport beneath (undertow). The net interaction can induce significant lateral mixing of the alongshore momentum of the mean currents, which is shown using a simplified three- dimension model of nearshore currents to explain much of the differences with observations.

Download or read book Wind and Wave Forcing of Longshore Currents Across a Barred Beach written by Dennis James Whitford and published by . This book was released on 1988 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Previous investigations of longshore currents have included simplifying assumptions and restriction (such as a planar beach, a steady and depth uniform flow, spatially-variant bed shear stress and turbulent momentum exchange, and the exclusion of surface wind stress. These assumptions are quantitatively investigated by calculating the relative importance of each term in the longshore momentum balance with an emphasis on the relative importance of wind forcing across the barred nearshore. Wind and wave forcing of longshore currents across a barred beach are examined using both a numerical model and field measurements. A local momentum balance was measured at various locations across the surf zone during the SUPERDUCK experiment held at the USACE CERC Field Research Facility, Duck, N.C. in October 1986. A moveable sled was instrumented with pressure, current, and wind sensors to measure the various terms in the longshore momentum equation. Stability-dependent atmospheric drag coefficients for the surf zone are determined from wind stress measurements acquired just beyond the surf zone and wind speed measurements acquired from an anemometer atop the 9 m sled mast. Breaking waves were visually identified and electronically marked on the data tapes. Keywords: Ocean currents; Air water interactions; Nearshore surf zone; Wind stress; Theses. (EDC).

Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 956 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Compilation of Theses Abstracts October 1994 September 1995 written by United States. Naval Postgraduate School, Monterey, CA. and published by . This book was released on 1995 with total page 564 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A Summary of Research 1995 written by United States. Naval Postgraduate School, Monterey, CA. and published by . This book was released on 1995 with total page 588 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Naval Research Reviews written by and published by . This book was released on 1998 with total page 356 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oceanography of the Nearshore Coastal Waters of the Pacific Northwest Relating to Possible Pollution written by Oregon State University and published by . This book was released on 1971 with total page 644 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Application of Short crested Wave Theory in the Design of Three Dimensional Coastal Hydrodynamic Models written by William Leo Wood and published by . This book was released on 1980 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: In spring 1973 a series of field experiments was initiated to investigate the three dimensional structure of a coastal hydrodynamic system. These field investigations supported the concept that short-crested wave theory is applicable to modeling of incident wind-wave transformations from offshore to the outer surf zone. Application of short-crested wave theory to the design of coastal hydrodynamic models was also considered appropriate because of the theories inherent three dimensional structure. Concurrent with this work two field experiments were conducted in 1974 and 1976 to measure vertical and horizontal distribution of longshore current velocity and to monitor temporal variations in current velocity at a point. In fall 1978 a series of experimental laboratory investigations was initiated to make precise measurements, at close spatial intervals, of wave height decay after breaking. These experiments were carried out to determine a wave height decay expression based upon the assumption that an appropriate physical conceptualization of wave energy dissipation after breaking must consider turbulence dominant to bottom friction. This report presents a detailed summary of these investigations and their results. (Author).

Download or read book A Mixing Mechanism in the Nearshore Region written by Uday Putrevu and published by . This book was released on 1994 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book River Coastal and Estuarine Morphodynamics RCEM 2007 Two Volume Set written by C. Marjolein Dohmen-Janssen and published by CRC Press. This book was released on 2019-08-22 with total page 1271 pages. Available in PDF, EPUB and Kindle. Book excerpt: Around the world, many people live, work and recreate in river, estuarine and coastal areas, systems which are also important wildlife habitats. It is imperative to understand the physics of such systems. A key element here is morphodynamics: the mutual interaction and adjustment of landform topography and fluid dynamics involving the motion of sed

Download or read book Advances in Coastal and Ocean Engineering written by Philip L. F. Liu and published by World Scientific. This book was released on 1999 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the last two decades, one of the most important research accomplishments in coastal hydrodynamics has been the development of accurate numerical models for nonlinear water wave propagation over a complex bathymetry from a relatively deep-water depth into the surf zone. This book contains five excellent papers reviewing different methodologies in various aspects of wave modeling; the authors are active researchers who have made original contributions to these subjects.

Download or read book Coastal Engineering 2004 Proceedings Of The 29th International Conference In 4 Vols written by Jane Mckee Smith and published by World Scientific. This book was released on 2005-04-08 with total page 4836 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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:

Download or read book Introduction to Nearshore Hydrodynamics written by Ib A. Svendsen and published by World Scientific. This book was released on 2006 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is intended as an introductory textbook for graduate students and as a reference book for engineers and scientists working in the field of coastal engineering. As such it gives a description of the theories for wave and nearshore hydrodynamics. It is meant to de-mystify the topics and hence starts at a fairly basic level. It requires knowledge of fluid mechanics equivalent to a first year graduate level. At the end of each topic, an attempt is made to give an overview of the present stage of the scientific development in that area with numerous references for further studies.

Download or read book Marine Turbulence written by Helmut Z. Baumert and published by Cambridge University Press. This book was released on 2005-04-04 with total page 664 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book gives a comprehensive overview of marine turbulence and mixing for students, scientists, engineers.

Download or read book A Guide to Modeling Coastal Morphology written by Dano Roelvink and published by World Scientific. This book was released on 2012 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt: Process-based morphodynamic modelling is one of the relatively new tools at the disposal of coastal scientists, engineers and managers. On paper, it offers the possibility to analyse morphological processes and to investigate the effects of various measures one might consider to alleviate some problems. For these to be applied in practice, a model should be relatively straightforward to set up. It should be accurate enough to represent the details of interest, it should run long enough and robustly to see the real effects happen, and the physical processes represented in such a way that the sediment generally goes in the right direction at the right rate. Next, practitioners must be able to judge if the patterns and outcomes of the model are realistic and finally, translate these colour pictures and vector plots to integrated parameters that are relevant to the client or end user. In a nutshell, this book provides an in-depth review of ways to model coastal processes, including many hands-on exercises.