scholarly journals Numerical Modeling of Irregular Water Wave Transformation

2014 ◽  
Vol 2014 ◽  
pp. 1-8
Author(s):  
K. M. Fassieh ◽  
O. Fahmy ◽  
M. A. Zaki
Keyword(s):  
Experimental Data ◽  
Energy Dissipation ◽  
Water Wave ◽  
Surf Zone ◽  
Nile Delta ◽  
Coastal Areas ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Random Wave ◽  
Nile Delta Coast

Propagation of irregular water wave from deep water to a shoreline has been numerically modeled. Linear and irregular waves are considered. Model equations govern effects of shoaling, refraction, and diffraction over a varying bathymetry. The model requires the input of the incoming directional random sea at the offshore boundary. Statistical energy dissipation model is incorporated to predict realistically energy losses due to wave breaking in surf zone. Unlike most of the previous models, this model can predict wave transformation in surf zone where energy dissipation and bottom friction must be taken into consideration. The model does not have the limitation of parabolic approximation models (PAM) that are valid only in case of weak refraction. Finite difference approximations have been used to solve the governing equation. The model results are compared with experimental data for directional random wave propagation over a submerged shoal. Good agreements between the model results and experimental data are shown. Applicability of the model to real coastal areas is shown by application to coastal areas along the Nile Delta Coast, Egypt.

scholarly journals TRANSFORMATION OF RANDOM BREAKING WAVES ON SURF BEAT

1986 ◽  
Vol 1 (20) ◽  
pp. 9 ◽  
Author(s):  
William R. Dally ◽  
Robert G. Dean
Keyword(s):  
Surf Zone ◽  
Wave Model ◽  
Breaking Waves ◽  
Wave Transformation ◽  
Random Wave ◽  
Data Sets ◽  
Data Set ◽  
Wave Decay ◽  
Mean Water Level ◽  
Good Agreement

Based on a previous study by the authors of regular breaking waves in the surf zone, a model for random wave transformation across the nearshore region is developed. The results of a laboratory investigation of the effect of a steady opposing current on the wave decay process are presented and a proposed governing equation verified. Surf beat effects on wave transformation are then included in the model by representing the long wave as a temporally and spatiallyvarying current and mean water level. The concept of an equivalent water depth, which contains the effect of the current, is introduced and then included in a stochastic form in the random wave model. Surf beat is found to noticeably increase the decay of the root mean square wave height, especially in the inner surf where the beat is strongest. Comparison of the models to two field data sets show very good agreement for Hotta and Mizuguchi (1980), but rather poor for Thornton and Guza (1983). Possible explanations for the unexpected behavior of the second data set, pertaining to filtering, are discussed. Finally, a possible explanation for the dependence of random wave decay on deepwater steepness, noted by Battjes and Stive (1985), is presented.

Assessment of random wave energy dissipation due to submerged aquatic plants in shallow water using deep water wave conditions

2021 ◽  
pp. 147509022110399
Author(s):  
Dag Myrhaug ◽  
Pierre-Yves Henry
Keyword(s):  
Energy Dissipation ◽  
Shallow Water ◽  
Deep Water ◽  
Aquatic Plants ◽  
Wave Energy ◽  
Water Wave ◽  
Random Wave ◽  
Wave Energy Dissipation ◽  
Submerged Aquatic Plants ◽  
Deep Water Wave

This article addresses the random wave energy dissipation due to submerged aquatic plants in shallow water based on deep water wave conditions including estimation of wave damping. The motivation is to provide a simple engineering tool suitable to use when assessing random wave damping due to small patches of plants in shallow water. Examples of application for typical field conditions are provided. The present method versus common practice is discussed. A possible application of the outcome of this study is that it can be used as a parameterization of wave energy dissipation due to vegetation patches of limited size in operational estuarine and coastal circulation models.

scholarly journals IRREGULAR WAVE TRANSFORMATION AFFECTED BY OPPOSING CURRENTS

1986 ◽  
Vol 1 (20) ◽  
pp. 53
Author(s):  
Shigeki Sakai ◽  
Kouestu Hiyamizu ◽  
Hiroshi Saeki
Keyword(s):  
Wave Height ◽  
Present Model ◽  
Surf Zone ◽  
Transformation Model ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Irregular Wave ◽  
Sea Bed ◽  
Dimensionless Unit ◽  
Deep Water Wave

Transformation of irregular waves affected by opposing currents on a sloping sea bed was discussed, experimentally and theoretically. It was found that representative values of wave height, such as a significant wave height, are larger before breaking and the wave height decaying occurs more promptly in a surf zone as opposing currents become dominant, and that characteristics of a irregular wave transformation are determined by the dimensionless unit width discharge q* and the deep water wave steepness. This means that the effects of opposing currents on irregular wave transformation are qualitatively identical to that on the regular waves. A transformation model of irregular waves affected by opposing currents was presented. In the model, formulations for a regular wave transformation, in which the effects of opposing currents were taken into account, were applied to individual waves defined by zero-down" cross-method from irregular wave profiles. Comparisons between experimental results and the prediction by the model showed that the present model gives a good explanation for wave height distributions and the experimental finding that the surf zone is moved offshore by opposing currents.

Numerical Simulation of Wave Transformation Across the Surf Zone Over a Steep Bottom

2010 ◽  
Author(s):  
Tai-Wen Hsu ◽  
Ta-Yuan Lin ◽  
Hwung-Hweng Hwung ◽  
Yaron Toledo ◽  
Aron Roland
Keyword(s):  
Energy Dissipation ◽  
Wave Breaking ◽  
Surf Zone ◽  
Numerical Models ◽  
Dissipation Factor ◽  
Wave Transformation ◽  
Bottom Slope ◽  
Mild Slope Equation ◽  
Efficient Scheme ◽  
Sloping Beach

The combined effect of shoaling, breaking and energy dissipation on a sloping bottom was investigated. Based on the conservation principle of wave motion, a combined shoaling and bottom slope coefficient is included in the mild-slope equation (MSE) which is derived as a function of the bottom slope perturbed to the third-order. The model incorporates the nonlinear shoaling coefficient and energy dissipation factor due to wave breaking to improve the accuracy of the simulation prior to wave breaking and in the surf zone over a steep bottom. The evolution equation of the MSE is implemented in the numerical solution which provides an efficient scheme for describing wave transformation in a large coastal area. The model validity is verified by comparison to accurate numerical models, laboratory experiments and analytical solutions of waves travelling over a steep sloping beach.

Wave Height Variation Across Surf Zone of Bar Type Profile

2009 ◽  
Author(s):  
Tai-Wen Hsu ◽  
Kun-Sian Lai
Keyword(s):  
Energy Dissipation ◽  
Wave Height ◽  
Analytical Solutions ◽  
Wave Energy ◽  
Hydraulic Jump ◽  
Surf Zone ◽  
Wave Transformation ◽  
Height Variation ◽  
Wave Energy Dissipation ◽  
Theoretical Results

Analytical solutions for wave height decay due to shoaling and breaking on a bar type profile are presented. A macroscopic analogy between an idealized surf zone and a hydraulic jump are incorporated in the theory to account for wave transformation and energy dissipation in the surf zone. The theoretical results are fairly compared with laboratory observations. Key parameters that influence wave energy dissipation in the surf zone are investigated.

scholarly journals WAVE HEIGHT DISTRIBUTION AND WAVE GROUPING IN SURF ZONE

1982 ◽  
Vol 1 (18) ◽  
pp. 4 ◽  
Author(s):  
Hajime Mase ◽  
Yuichi Iwagaki
Keyword(s):  
Wave Height ◽  
Surf Zone ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Height Distribution ◽  
Frequency Distributions ◽  
Irregular Wave ◽  
Wave Height Distribution ◽  
Wave Heights ◽  
Deep Water Wave

The main purpose of this paper is to propose a model for prediction of the spatial distributions of representative wave heights and the frequency distributions of wave heights of irregular waves in shallow-water including the surf zone. In order to examine the validity of the model, some experiments of irregular wave transformation have been made. In addition, an attempt has been made to clarify the spatial distribution of wave grouping experimentally. Especially the present paper focuses finding the effects of the bottom slope and the deep-water wave steepness on the wave height distribution and wave grouping.

scholarly journals A STUDY ON WAVE TRANSFORMATION INSIDE SURF ZONE

1966 ◽  
Vol 1 (10) ◽  
pp. 14 ◽  
Author(s):  
Kiyoshi Horikawa ◽  
Chin-Tong Kuo
Keyword(s):  
Experimental Data ◽  
Wave Height ◽  
Surf Zone ◽  
The Other ◽  
Wave Transformation ◽  
Analytical Treatment ◽  
Numerous Data ◽  
Wave Height Attenuation ◽  
Sloping Beach ◽  
Horizontal Bottom

The wave transformation inside surf zone is treated analytically m this paper under the several appropriate assumptions. The theoretical curves computed numerically have a consistant agreement with the experimental data in the case of wave transformation on a horizontal bottom. On the other hand, m the case of wave transformation on a uniformly sloping beach, the analytical treatment seems to be inadequate to clarify the actual phenomena. Besides them the numerous data on wave height attenuation and others are presented m the graphical forms.

The coastal refraction-diffraction wave propagation model

1995 ◽  
Vol 17 (4) ◽  
pp. 6-12
Author(s):  
Nguyen Tien Dat ◽  
Dinh Van Manh ◽  
Nguyen Minh Son
Keyword(s):  
Wave Propagation ◽  
Field Data ◽  
Surf Zone ◽  
Propagation Model ◽  
Wave Transformation ◽  
Diffraction Effect ◽  
Linear Wave ◽  
Diffraction Wave ◽  
Linear Wave Propagation ◽  
Wave Propagation Model

A mathematical model on linear wave propagation toward shore is chosen and corresponding software is built. The wave transformation outside and inside the surf zone is considered including the diffraction effect. The model is tested by laboratory and field data and gave reasonables results.

scholarly journals Time Scale for Scour Beneath Pipelines Due to Long-Crested and Short-Crested Nonlinear Random Waves Plus Current

2021 ◽  
Vol 9 (2) ◽  
pp. 114
Author(s):  
Dag Myrhaug ◽  
Muk Chen Ong
Keyword(s):  
Time Scale ◽  
Current Flow ◽  
Irregular Waves ◽  
Wave Crest ◽  
Random Wave ◽  
Random Waves ◽  
Flow Conditions ◽  
Regular Waves ◽  
Nonlinear Random Waves ◽  
2D And 3D

This article derives the time scale of pipeline scour caused by 2D (long-crested) and 3D (short-crested) nonlinear irregular waves and current for wave-dominant flow. The motivation is to provide a simple engineering tool suitable to use when assessing the time scale of equilibrium pipeline scour for these flow conditions. The method assumes the random wave process to be stationary and narrow banded adopting a distribution of the wave crest height representing 2D and 3D nonlinear irregular waves and a time scale formula for regular waves plus current. The presented results cover a range of random waves plus current flow conditions for which the method is valid. Results for typical field conditions are also presented. A possible application of the outcome of this study is that, e.g., consulting engineers can use it as part of assessing the on-bottom stability of seabed pipelines.

Structural Safety Assessment of a 1100 TEU Container Ship, Based on a Enhanced Long Term Fatigue Analysis

2014 ◽  
Vol 1036 ◽  
pp. 935-940
Author(s):  
Leonard Domnisoru ◽  
Ionica Rubanenco ◽  
Mihaela Amoraritei
Keyword(s):  
Safety Assessment ◽  
Safety Evaluation ◽  
Irregular Waves ◽  
Structural Safety ◽  
Random Wave ◽  
Wave Loads ◽  
Strength Assessment ◽  
Integrated Method ◽  
Hydroelastic Response

This paper is focused on an enhanced integrated method for structural safety assessment of maritime ships under extreme random wave loads. In this study is considered an 1100 TEU container test ship, with speed range 0 to 18 knots. The most comprehensive criteria for ships structural safety evaluation over the whole exploitation life is based on the long term ship structures analysis, that includes: stress hot-spots evaluation by 3D/1D-FEM hull models, computation of short term ship dynamic response induced by irregular waves, long term fatigue structure assessment. The analysis is enhanced by taking into account the ships speed influence on hydroelastic response. The study includes a comparative analysis on two scenarios for the correlation between the ships speed and waves intensity. The standard constant ship speed scenario and CENTEC scenario, with total speed loss at extreme waves condition, are considered. Instead of 20 years ship exploitation life estimated by classification societies rules from the long term structural safety criteria, the enhanced method has predicted more restrictive values of 14.4-15.7 years. The numerical analyses are based on own software and user subroutines. The study made possible to have a more realistic approach of ships structural strength assessment, for elastic and faster ships as container carriers, in compare to the standard one based only on naval rules, delivering a method with higher confidence in the designed structural safety.

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