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 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.

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 FLOW COMPUTATIONS NEARBY A STORM SURGE BARRIER UNDER CONSTRUCTION WITH TWO-DIMENSIONAL NUMERICAL MODELS

1986 ◽  
Vol 1 (20) ◽  
pp. 143
Author(s):  
H.E. Klatter ◽  
J.M.C. Dijkzeul ◽  
G. Hartsuiker ◽  
L. Bijlsma
Keyword(s):  
Numerical Model ◽  
Storm Surge ◽  
Field Data ◽  
Numerical Models ◽  
Flow Patterns ◽  
Scale Model ◽  
Energy Losses ◽  
Local Energy ◽  
Two Dimensional ◽  
Physical Scale

This paper discusses the application of two-dimensional tidal models to the hydraulic research for the storm surge barrier in the Eastern Scheldt in the Netherlands. At the site of the barrier local energy losses dominate the flow. Three methods are discussed for dealing with these energy losses in a numerical model based on the long wave equations. The construction of the storm surge barrier provided extensive field data for various phases of the construction of the barrier and these field data are used as a test case for the computation at methods developed. One method is preferred since it gives good agreement between computations and field data. The two-dimensional flow patterns, the discharge and the head-difference agree well,, The results of scale model tests were also available for comparison. This comparison demonstrated that depth-averaged velocities, computed by a two-dimensional numerical model, are as accurate as values obtained from a large physical scale model. Even compicated flow patterns with local energy losses and sharp velocity gradients compared well.

Sediment size distribution and composition in a reservoir affected by severe water level fluctuations

2016 ◽  
Vol 540 ◽  
pp. 158-167 ◽  
Author(s):  
Pilar López ◽  
José A. López-Tarazón ◽  
Joan P. Casas-Ruiz ◽  
Marcelo Pompeo ◽  
Jaime Ordoñez ◽  
...  
Keyword(s):  
Water Level ◽  
Size Distribution ◽  
Water Level Fluctuations ◽  
Sediment Size

scholarly journals 3D numerical modeling of flow and sediment transport in rivers and open channels

2019 ◽  
Vol 3 (1) ◽  
pp. 23-36
Author(s):  
Le Song Giang ◽  
Tran Thi My Hong
Keyword(s):  
Boundary Condition ◽  
Sediment Transport ◽  
Numerical Model ◽  
Differential Equations ◽  
Water Level ◽  
Suspended Sediment ◽  
Three Dimensional ◽  
River Bed ◽  
Suspended Sediment Concentrations ◽  
Flow And Sediment Transport

Numerical model is a useful tool in studying the flow and sediment transport, change in river bed and is built on solving governing differential equations. Numerical model has many different levels and three-dimensional model is the highest level, allowing detailed simulation of flow and sediment transport process in 3D space. The paper presents a method calculating three - dimensional flow and sediment transport in the open channel. Water level and flow velocity are solved from three-dimensional equations with hydrostatic hypothesis. Concentration of suspended sediment, bottom sediment and bottom evolution is solved from transport equations. The governing differential equations in the "sigma" transform coordinate system are solved by finite volume method on unstructured grid of quadrilateral elements. Boundary condition of water level or flow will be imposed on open boundary. For suspended sediment concentrations in the injected phase, suspended sediment concentrations are applied and the outflow phase applies free drainage conditions. This method of calculation was tested with the problem of curved channel sediment transport which was studied experimentally by Odgaard and Bergs. Calculation results are quite consistent with the measured data. In order to test the practical applicability, this method is also tested with the problem of sediment transport in Cu lao Pho islet on Dong Nai river. To solve the matter of hydraulic boundary condition of this problem, the model of Cu lao Pho islet is integrated into the Sai Gon - Dong Nai river system model. Results of the calculation of the river bed evolution of the Cu lao Pho islet on the Dong Nai river also show that this calculation method gives results consistent with the rule and can be used in practical research.  

scholarly journals ANOMALOUS DISPERSION OF FOURIER COMPONENTS OF SURFACE GRAVITY WAVES IN THE NEAR SHORE AREA

1978 ◽  
Vol 1 (16) ◽  
pp. 12 ◽  
Author(s):  
Fritz Busching
Keyword(s):  
Water Level ◽  
Storm Surge ◽  
North Sea ◽  
Gravity Waves ◽  
Anomalous Dispersion ◽  
Beach Profile ◽  
Severe Storm ◽  
Surface Gravity Waves ◽  
Near Shore ◽  
Frequency Components

Water level deflections ri (t) have been measured synchronously at some positions in a beach profile on the isle of SYLT / North Sea during severe storm surge conditions as well as at attenuating wave action. A steadily increasing wave period T in the upbeach direction, turning out from strip chart evaluations, is in accordance with the result of FOURIER syntheses. Near shore wave deformation is explained by ANOMALOUS dispersion of the frequency components.

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.

scholarly journals MODELING OF BERM FORMATION AND EROSION AT THE SOUTHERN COAST OF THE CASPIAN SEA

2020 ◽  
pp. 19
Author(s):  
Mohammad Tabasi ◽  
Mohsen Soltanpour ◽  
Takayuki Suzuki ◽  
Ravindra Jayaratne
Keyword(s):  
Sediment Transport ◽  
Caspian Sea ◽  
Mass Conservation ◽  
Conservation Equation ◽  
Transport Equations ◽  
Southern Coast ◽  
Beach Profile ◽  
The Caspian Sea ◽  
Erosion Model ◽  
Wave Conditions

Cross-shore beach profile data from field measurements performed at six locations on the southern coast of the Caspian Sea are used to investigate bathymetry change due to various wave conditions. Beach profile measurements are analyzed and subsequently compared with the results of a berm formation and erosion model. The model comprises distinct empirical sediment transport equations for predicting the cross-shore sediment transport rate under various wave conditions. To yield a berm formation and erosion model, empirical cross-shore sediment transport equations are combined with the mass conservation equation. Simulations results obtained from the model compared well with the measurements, proving the capability of the model in simulating berm formation and erosion evolution.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/FTgAr73h5rA

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