A numerical model for beach profile development

1985 ◽  
Vol 12 (1) ◽  
pp. 231-234 ◽  
Author(s):  
A. Swain ◽  
J. R. Houston
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Key Words ◽  
Laboratory Tests ◽  
Field Data ◽  
Time Dependent ◽  
Water Level Fluctuations ◽  
Beach Profile ◽  
Sediment Size ◽  
Profile Development

A time-dependent numerical model that calculates beach profile development due to offshore sediment transport is developed. The model allows variable wave conditions, water level fluctuations due to tide, arbitrary bathymetry, and sediment size. The accuracy of the model is tested by comparison of calculations with laboratory and with field data. The agreement between calculated and measured beach profiles is good. Key words: numerical model, beach profile, laboratory tests, field data.

scholarly journals ONSHORE-OFFSHORE SEDIMENT TRANSPORT NUMERICAL MODEL

1984 ◽  
Vol 1 (19) ◽  
pp. 84
Author(s):  
A. Swain ◽  
J.R. Houston
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Water Level ◽  
Storm Surge ◽  
Field Data ◽  
Water Level Fluctuations ◽  
Beach Profile ◽  
Sediment Size ◽  
Wave Conditions ◽  
Profile Development

A numerical model is presented for calculating beach profile development due to offshore sediment transport and tested with laboratory and field data. The model allows variable wave conditions, water level fluctuations due to tide and storm surge, arbitrary bathymetry, and arbitrary sediment size. The agreement between calculated and measured beach profile erosion is good.

A RANS numerical model for cross-shore beach profile evolution

2020 ◽  
Author(s):  
Julio Garcia-Maribona ◽  
Javier L. Lara ◽  
Maria Maza ◽  
Iñigo J. Losada
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Transport Model ◽  
Numerical Models ◽  
Computational Cost ◽  
Physical Modelling ◽  
Computational Effort ◽  
Beach Profile ◽  
Time Step ◽  
Wave Conditions

<p>The evolution of the cross-shore beach profile is tightly related to the evolution of the coastline in both small and large time scales. Bathymetry changes in extreme maritime events can also have important effects on coastal infrastructures such as geotechnical failures of foundations or the modification of the incident wave conditions towards a more unfavourable situation.</p><p>The available strategies to study the evolution of beach profiles can be classified in analytical, physical and numerical modelling. Analytical solutions are fast, but too simplistic for many applications. Physical modelling provides trustworthy results and can be applied to a wide variety of configurations, however, they are costly and time-consuming compared to analytical strategies. Finally,  numerical approaches offer different balances between cost and precision depending on the particular model.</p><p>Some numerical models provide greater precision in the beach profile evolution, but incurring in a prohibitive computational cost for many applications. In contrast, the less expensive ones assume simplifications which do not allow to correctly reproduce significant phenomena of the near-shore hydrodynamics such as wave breaking or undertow currents, neither to predict important features of the beach profile like breaker bars.</p><p>In this work, a new numerical model is developed to reproduce the main features of the beach profile and hydrodynamics while maintaining an affordable computational cost. In addition, it is intended to reduce to the minimum the number of coefficients that the user has to provide to make the model more predictive.</p><p>The model consists of two main modules. Firstly, the already existing 2D RANS numerical model IH2VOF is used to compute the hydrodynamics. Secondly, the sediment transport model modifies the bathymetry according to the obtained hydrodynamics. The new bathymetry is then considered in the hydrodynamic model to account for it in the next time step.</p><p>The sediment transport module considers bedload and suspended transports separately. The former is obtained with empirical formulae. In the later,the distribution of sediment concentration in the domain is obtained by solving an advective-diffusive transport equation. Then, the sedimentation and erosion rates are obtained along the seabed.<br>Once these contributions are calculated, a sediment balance is performed in every seabed segment to determine the variation in its level.</p><p>With the previously described strategy, the resulting model is able to predict not only the seabed changes due to different wave conditions, but also the influence of this new bathymetry in the hydrodynamics, capturing features such as the generation of a breaker bar, displacement of the breaking point or variation of the run-up over the beach profile. To validate the model, the numerical results are compared to experimental data.</p><p>An important novelty of the present model is the computational effort required to perform the simulations, which is significantly smaller than the one associated to existing models able to reproduce the same phenomena.</p>

scholarly journals NUMERICAL SIMULATION OF SEAWALL- BEACH PROFILE INTERACTION IN RUNUP ZONE

2017 ◽  
pp. 21
Author(s):  
Berna Ayat Aydogan ◽  
Nobuhisa Kobayashi ◽  
Yalçın Yüksel ◽  
Burak AydoÄŸan
Keyword(s):  
Numerical Model ◽  
Laboratory Tests ◽  
Surf Zone ◽  
Vertical Wall ◽  
Small Scale ◽  
Scour Depth ◽  
Beach Profile ◽  
The Cross ◽  
Run Up ◽  
Offshore Transport

This study aimed to determine beach response in the presence of a vertical wall placed in the run-up zone. The responses of natural beach and the beach with a seawall with two different configurations were studied numerically. The capability and limitation of the cross-shore numerical model CSHORE in simulating the cross-shore transformation and the beach evolution in front of a seawall situated inside the surf zone was examined. Numerical model results were compared with small scale laboratory tests (Yüksel et. al, 2014). Offshore transport was observed in all three tests and the model was shown to predict the same trends in profile evolution. Scour depth in front of the vertical wall was correctly captured by the numerical model.

scholarly journals APPLICATION OF XBEACH TO MODEL STORM RESPONSE ON A MACROTIDAL GRAVEL BARRIER

2011 ◽  
Vol 1 (32) ◽  
pp. 39 ◽  
Author(s):  
Amaia Ruiz de Alegria-Arzaburu ◽  
Jon J Williams ◽  
Gerhard Masselink
Keyword(s):  
Sediment Transport ◽  
Hydraulic Conductivity ◽  
Numerical Model ◽  
Morphological Changes ◽  
Coastal Engineering ◽  
Beach Profile ◽  
Morphological Response ◽  
Total Drag ◽  
Storm Response ◽  
Gravel Beach

The process-based XBeach numerical model has been used to simulate storm-induced morphological response on a macrotidal gravel barrier located in southwest UK. Using well-established parameterisation to define all relevant hydrodynamic, groundwater and sediment processes, the model was applied in 1D mode to simulate observed storm-induced beach profile responses. Investigations showed that the morphological response of the beach was best modelled using a total drag coefficient, CD, of 0.007, and a hydraulic conductivity, K, of 0.05ms-1. Results obtained from simulations with and without beach groundwater highlighted the need to account for groundwater effects when modelling morphological changes on gravel beaches. The model has been found unable of reproducing the formation of a berm, thus, beach recovery conditions cannot be modelled. This is mainly attributed to the fact that XBeach models long waves rather than individual waves, and thus it cannot simulate individual swash events that contribute to onshore sediment transport and berm accretion. However, the model is shown to provide good estimates of post-storm gravel beach/barrier profiles, and to define the threshold for overwash occurrence. Both attributes have utility in a range of practical coastal engineering and management applications.

scholarly journals A NUMERICAL MODEL OF CROSS-SHORE BEACH PROFILE EVOLUTION: THEORY, MODEL DEVELOPMENT AND APPLICABILITY

2018 ◽  
pp. 69
Author(s):  
Mohammad Tabasi ◽  
Mohsen Soltanpour ◽  
Ravindra Jayaratne ◽  
Tomoya Shibayama ◽  
Akio Okayasu
Keyword(s):  
Numerical Model ◽  
Field Data ◽  
Suspended Sediment Concentration ◽  
Surf Zone ◽  
Model Development ◽  
Sediment Concentration ◽  
Theory Model ◽  
Beach Profile ◽  
The North ◽  
North And South

A practical numerical model was developed to simulate cross-shore profile evolution at two coastal sites in Iran. The model consists of three sub-models for calculating wave and current, sediment transport, and bed level changes. Validation and calibration of the model was carried out using the measured field data on the north and south coasts of Iran, where historic measurements of cross-shore beach profiles and wave conditions have been recorded. The model is formulated for calculating cross-shore sediment transports in and outside the surf zone by the product of time-averaged suspended sediment concentration under three different mechanisms and undertow velocity. The comparisons between the model results and field data show reasonable agreement for both coastal sites and will be capable of applying it to other coastal sites with modifications to the free parameters.

Numerical Simulation of Dynamic Shoreline Changes Behind a Detached Breakwater by Using an Equilibrium Formula

2017 ◽  
Author(s):  
Jung Lyul Lee ◽  
John Rong-Chung Hsu
Keyword(s):  
Sediment Transport ◽  
Numerical Model ◽  
Shoreline Change ◽  
Beach Profile ◽  
Excellent Performance ◽  
Shoreline Changes ◽  
Shoreline Evolution ◽  
Equilibrium Beach Profile ◽  
Shape Equation ◽  
The One

Salient and tombolo are common features found in the lee of detached breakwaters. The empirical parabolic bay shape equation (PBSE) can be applied when their planform is fully developed, whereas numerical model is required to simulate the dynamic shoreline evolution prior to the planform reaching static equilibrium. This paper reports the excellent performance of PBSE through the comparison with labaratory results and the development of a numerical model for dynamic shoreline change that utilizes the concept of PBSE and equilibrium beach profile. Formulation proposed for sediment transport rate is theoretically compared with that in GENESIS. The governing equation for the combined shoreline response model is based on the one-line beach model, which includes shoreline changes owing to longshore and cross-shore sediment transport. Finally, numerical results reveal, by comparing with an experimental case in the laboratory, that the model is adequate to successively simulating the dynamic evolutions of the shoreline behind a detached breakwater.

Comment évaluer l'érosion d'une vallée sous l'écoulement de rupture d'un barrage

1986 ◽  
Vol 13 (4) ◽  
pp. 474-484
Author(s):  
M. Kenfaoui ◽  
C. Marche
Keyword(s):  
Experimental Study ◽  
Sediment Transport ◽  
Key Words ◽  
Laboratory Tests ◽  
Dam Break ◽  
Steady Flows ◽  
Transport Models ◽  
Wave Parameters ◽  
Bed Erosion ◽  
Fixed Beds

This laboratory experimental study deals with dam-break flows on movable beds. It demonstrates significant differences between these wave parameters and values of the same parameters estimated on fixed beds. Moreover it is shown that under specific conditions some sediment transport models for steady flows can be applied to estimate bed erosion for this particular type of flow. Key words: dam, dam-break, break flows, erosion, laboratory tests.

scholarly journals SEDIMENT TRANSPORT ON NEARLY-PRISMATIC BEACHES

1988 ◽  
Vol 1 (21) ◽  
pp. 128
Author(s):  
Marcel J.F. Stive ◽  
J.A. Roelvink
Keyword(s):  
Sediment Transport ◽  
Recent Progress ◽  
Dynamic Modelling ◽  
Two Dimensional ◽  
Random Waves ◽  
Beach Profile ◽  
Quantitative Modelling ◽  
Obliquely Incident ◽  
Current Systems ◽  
Profile Development

Recent progress in the quantitative modelling of the undertow has stimulated the modelling of cross-shore sediment transport. More so than before it seems now possible to attempt the dynamic modelling of beach profile development. Also, integration of dynamic cross-shore sediment transport formulations in horizontally two-dimensional models for watermotion and sediment transport has recently been suggested. This seems to be a first step of integrating depth-averaged 2DH-modelling with 2DV-profile- modelling. Here an overview is given of these developments and the understanding gained sofar of the several current systems and the induced sediment transport and morphology that are found in the situation of random waves normally and obliquely incident on beaches which vary not or only slowly alongshore.

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