Nearshore Wave and Current Dynamics

Nearshore Wave and Current Dynamics PDF Author: Bruce J. Morris
Publisher:
ISBN: 9781423525349
Category :
Languages : en
Pages : 100

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Book Description
Mean cross-shore wave height transformation and alongshore currents observed on near-planar and barred beaches are compared with predictions based on the nearshore numerical model Delft3D. Delft3D solves the two-dimensional, depth-averaged, momentum balance (2-DH) between forcing (by breaking waves and variations in mean surface elevation), changes in momentum flux, bottom stress and lateral mixing. The observations were acquired on the near-planar California beaches at Torrey Pines and Santa Barbara and the barred beach at Duck, N.C., and include a wide range of conditions with maximum mean currents of 1.5 m/s. The model has two free parameters, a depth dependent breaking term, gamma, and the bed roughness length, k sub s. An empirical formula to determine gamma a priori from the deep-water wave steepness and bed slope is developed, showing good agreement in the wave height transformation. Including rollers in the wave forcing results in improved predictions of the observed alongshore current structure by shifting the predicted velocity maxima shoreward and increasing the velocity in the trough of the bar compared with model predictions without rollers. On near-planar beaches and high-energy events on barred beaches, a one- dimensional (alongshore uniform bathymetry) model performs as well as 2-DH. On barred beaches under moderate conditions when alongshore non-uniform bathymetry prevails, the 2-DH model performs better than the 1-D model, particularly in the bar-trough region. Wave forcing balances the bottom stress with a second balance between alongshore variation in the mean surface elevation (pressure gradients) and the inertia of the alongshore current.

Nearshore Wave and Current Dynamics

Nearshore Wave and Current Dynamics PDF Author: Bruce J. Morris
Publisher:
ISBN: 9781423525349
Category :
Languages : en
Pages : 100

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Book Description
Mean cross-shore wave height transformation and alongshore currents observed on near-planar and barred beaches are compared with predictions based on the nearshore numerical model Delft3D. Delft3D solves the two-dimensional, depth-averaged, momentum balance (2-DH) between forcing (by breaking waves and variations in mean surface elevation), changes in momentum flux, bottom stress and lateral mixing. The observations were acquired on the near-planar California beaches at Torrey Pines and Santa Barbara and the barred beach at Duck, N.C., and include a wide range of conditions with maximum mean currents of 1.5 m/s. The model has two free parameters, a depth dependent breaking term, gamma, and the bed roughness length, k sub s. An empirical formula to determine gamma a priori from the deep-water wave steepness and bed slope is developed, showing good agreement in the wave height transformation. Including rollers in the wave forcing results in improved predictions of the observed alongshore current structure by shifting the predicted velocity maxima shoreward and increasing the velocity in the trough of the bar compared with model predictions without rollers. On near-planar beaches and high-energy events on barred beaches, a one- dimensional (alongshore uniform bathymetry) model performs as well as 2-DH. On barred beaches under moderate conditions when alongshore non-uniform bathymetry prevails, the 2-DH model performs better than the 1-D model, particularly in the bar-trough region. Wave forcing balances the bottom stress with a second balance between alongshore variation in the mean surface elevation (pressure gradients) and the inertia of the alongshore current.

Nearshore Dynamics and Coastal Processes

Nearshore Dynamics and Coastal Processes PDF Author: Kiyoshi Horikawa
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 552

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Book Description


Ocean Wave Dynamics

Ocean Wave Dynamics PDF Author: Ian Young
Publisher: World Scientific
ISBN: 9811208689
Category : Science
Languages : en
Pages : 396

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Book Description
Ocean Wave Dynamics is the most up-to-date book of its kind on the three main processes responsible for the generation and evolution of ocean waves: (i) atmospheric input from the wind, (ii) wave breaking and (iii) nonlinear interactions.Ocean waves are important for many reasons. They are the major environmental impact on in the design of coastal or offshore structures. Ocean waves are also fundamental to the processes of coastal flooding and beach erosion. They will play a major role in storm related coastal flooding which will rise in frequency as a result of sea level rise. Ocean waves are also an important part of the coupled ocean-atmosphere system. They determine the roughness of the ocean surface and hence have an impact on winds, fluxes of energy, gases and heat to the ocean and even the stability of ice sheets.Containing the latest research on ocean waves, it is a valuable resource for an overview of knowledge in this important field.Related Link(s)

Introduction to Coastal Dynamics and Shoreline Protection

Introduction to Coastal Dynamics and Shoreline Protection PDF Author: G. Benassai
Publisher: WIT Press
ISBN: 1845640543
Category : Technology & Engineering
Languages : en
Pages : 353

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Book Description
"Provides an integrated approach to coastal dynamics and shoreline protection, aided by the use of specific case studies" -- Back cover.

Numerical Modelling of Waves and Nearshore Dynamics in Fetch Limited Water Bodies

Numerical Modelling of Waves and Nearshore Dynamics in Fetch Limited Water Bodies PDF Author: Peter B. Hale
Publisher:
ISBN:
Category : Beach erosion
Languages : en
Pages : 94

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Book Description


Introduction To Nearshore Hydrodynamics

Introduction To Nearshore Hydrodynamics PDF Author: Ib A Svendsen
Publisher: World Scientific Publishing Company
ISBN: 9813102055
Category : Technology & Engineering
Languages : en
Pages : 748

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Book Description
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.

Ocean Wave Dynamics For Coastal And Marine Structures

Ocean Wave Dynamics For Coastal And Marine Structures PDF Author: Vallam Sundar
Publisher: World Scientific
ISBN: 9811236682
Category : Technology & Engineering
Languages : en
Pages : 362

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Book Description
The increase in exploration and exploitation of ocean resources, maritime trade and ocean energy have led to development of new concepts in the study of coastal and marine structures. These developments necessitate comprehensive and in-depth knowledge of ocean wave behavior in the offshore as well as in the nearshore, such as the phenomena of wave generation, propagation, deformation and its effects, which help to enlighten our understanding of its influence on coastal and offshore structures.Ocean Wave Dynamics for Coastal and Marine Structures is a recommended textbook for students and researchers in ocean sciences, engineering and related topics. It offers application of theoretical formulae to practical relevance through problem solving. This book will also be invaluable for professionals in ports, offshore and marine industries as well as consulting companies.

Hydrodynamics and sedimentation in wave-dominated coastal environments

Hydrodynamics and sedimentation in wave-dominated coastal environments PDF Author:
Publisher: Elsevier
ISBN: 008086953X
Category : Science
Languages : en
Pages : 476

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Book Description
Hydrodynamics and sedimentation in wave-dominated coastal environments

Shore Wave Modulation Due to Infragravity Waves in the Nearshore Zone, with Applications

Shore Wave Modulation Due to Infragravity Waves in the Nearshore Zone, with Applications PDF Author: Saad M. M. Abdelrahman
Publisher:
ISBN:
Category : Littoral drift
Languages : en
Pages : 140

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Book Description
The omni-present low frequency wave motion (30-300 sec) contains a substantial fraction of the total wave energy inside the surf zone. A more complete description of nearshore wave processes considers incident short period waves superposed on, and interacting with, long standing waves. The wind waves are modulated in amplitude, wavenumber and direction due to relatively slowly varying depth changes caused by the long waves. The energy in the wind wave band is enhanced by side band growth at the sum and difference frequencies of short and long waves (order 15% at the shoreline). The modulation is identified in the analysis of field data as a positive correlation between the long waves and the wind wave envelope near the shoreline. Considering oblique incident waves, a steady longshore current showing a non-vanishing current at the shoreline is found as a result of the non-linear interaction between monochromatic incident and infragravity waves. An analytical solution describing the unsteadiness of the longshore current is developed. Keywords include: Infragravity, Longshore Current, Sediment transport, and Surf zone dynamics. (Theses).

Dynamics of the Coastal Zone

Dynamics of the Coastal Zone PDF Author: Matteo Postacchini
Publisher: MDPI
ISBN: 3039284843
Category : Technology & Engineering
Languages : en
Pages : 182

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Book Description
The coastal zone is the host to many human activities, which have significantly increased in the last decades. However, sea level rise and more frequent storm events severely affect beaches and coastal structures, with negative consequences and dramatic impacts on coastal communities. These aspects add to typical coastal problems, like flooding and beach erosion, which already leading to large economic losses and human fatalities. Modeling is thus fundamental for an exhaustive understanding of the nearshore region in the present and future environment. Innovative tools and technologies may help to better understand coastal processes in terms of hydrodynamics, sediment transport, bed morphology, and their interaction with coastal structures. This book collects several contributions focusing on nearshore dynamics, and span among several time and spatial scales using both physical and numerical approaches. The aim is to describe the most recent advances in coastal dynamics.