Solving a harbor accretion problem: the case of Miller and, Îles-de-la-Madeleine, Quebec

1989 ◽  
Vol 16 (6) ◽  
pp. 924-935 ◽  
Author(s):  
Yvon Ouellet ◽  
François Anctil ◽  
Louis Desjardins
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Wave Climate ◽  
Physical Models ◽  
Diffraction Reflection ◽  
East Side ◽  
Littoral Drift ◽  
Reflection Model ◽  
The Impact ◽  
La Madeleine

This paper summarizes a group of studies regarding Millerand harbor, located on the Îles-de-la-Madeleine coast, which blocks most of the local littoral drift. The understanding and quantification of this sedimentological problem was first carried out using numerical models. Various schemes were then tested in two mobile-bed physical models. Finally, the impact of these solutions on the wave climate in the harbor and in the entrance channel was compared using a diffraction–reflection numerical model. The results show that accretion in Millerand harbor will only be controlled by the construction of a breakwater. This breakwater must close the east side of the harbor and must reach at least 2 m depth at its toe. It is also strongly recommended that two groins be built on the east-side beach to control the erosion of the cliff. The results of the diffraction–reflection model finally give some latitude to the harbor planners, as several schemes present satisfactory wave agitation maps. Key words: erosion, accretion, breakwater, diffraction–reflection, harbor, littoral drift, numerical model, physical model, wave hindcasting.

scholarly journals Coastal vulnerability of a pinned, soft-cliff coastline, II: assessing the influence of sea walls on future morphology

2014 ◽  
Vol 2 (1) ◽  
pp. 233-242 ◽  
Author(s):  
A. Barkwith ◽  
M. D. Hurst ◽  
C. W. Thomas ◽  
M. A. Ellis ◽  
P. L. Limber ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Morphological Changes ◽  
Numerical Models ◽  
Field Research ◽  
Wave Climate ◽  
Sediment Flux ◽  
Climate Data ◽  
Coastal Morphology ◽  
Coastal Evolution ◽  
The Impact

Abstract. Coastal defences have long been employed to halt or slow coastal erosion, and their impact on local sediment flux and ecology has been studied in detail through field research and numerical simulation. The non-local impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention. Morphological changes at this scale due to defending structures can be difficult to quantify or identify with field data. Engineering-scale numerical models, often applied to assess the design of modern defences on local coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older structures. We extend previous work to explore the influences of sea walls on the evolution and morphological sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East Yorkshire, UK, is used as a case study to explore model scenarios where the coast is both defended with major sea walls and allowed to evolve naturally were there are no sea defences. Using a mesoscale numerical coastal evolution model, observed wave-climate data are perturbed linearly to assess the sensitivity of the coastal morphology to changing wave climate for both the defended and undefended scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have a greater impact on sediment flux due to increased sediment availability along this part of the coast. Multiple defence structures, including those separated by several kilometres, were found to interact with each other, producing complex changes in coastal morphology under a changing wave climate. Although spatially and temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their up-drift side.

scholarly journals FINAL DESIGN OF THE NAGS HEAD BEACH NOURISHMENT PROJECT USING A LONGSHORE NUMERICAL MODEL

2012 ◽  
Vol 1 (33) ◽  
pp. 64 ◽  
Author(s):  
Haiqing Liu Kaczkowski ◽  
Timothy W Kana
Keyword(s):  
Numerical Model ◽  
Large Scale ◽  
Numerical Models ◽  
Normal Wave ◽  
Beach Nourishment ◽  
Shoreline Evolution ◽  
Longshore Transport ◽  
Final Design ◽  
Model Setup ◽  
The Impact

Nags Head, located at the northeastern part of North Carolina in the U.S., has sustained chronic erosion over the past 50 years. In 2005, Coastal Science & Engineering (CSE) was retained by the town of Nags Head to develop an interim beach restoration plan. Profile volume change was used in the planning and preliminary design of the project, and longshore and cross-shore numerical models were used in the final design to refine the preliminary nourishment plan and increase potential longevity of the project. This paper focuses on the key factors of the longshore numerical model setup for the project. These include model selection, input data and parameters, model calibration, and applications under different design alternatives. The Generalized Model for Simulating Shoreline Changes (GENESIS) was used in this study to evaluate shoreline evolution under normal wave conditions during various stages of the design life following the beach nourishment project. The model was used to identify the potential occurrence of erosional hotspots and to optimize the nourishment design so that the effects of such hotspots could be avoided or minimized where possible. Model results were also used to evaluate the impact of borrow area dredging on longshore transport in the project area and the impact of nourishment on shoaling in the adjacent inlet. The project encompasses 10.11 miles (mi) (16.28 kilometers-km) of ocean shoreline, and the design nourishment volume is based on the total permitted volume of 4 million cubic yards (cy) (3 million cubic meters-m³). [Note: As-built length was 10.0 mi and volume was 4.615 million cubic yards.] The final design has fill densities varying from north to south in relation to historical erosion rates and model projections. The average fill density is 75 cubic yards per foot (cy/ft) (188 m³/m) and ranges from 38 cy/ft to 150 cy/ft (95 m³/m to 375 m³/m). In conclusion, it is shown that the numerical model selected in this study was capable of predicting the overall performance of the large scale beach nourishment project in Nags Head as well as the performance at a particular location within or adjacent to the project, and its design methods can offer guidance to future projects.

scholarly journals Numerical Modeling of Flow Field in Morning Glory Spillways and Determining Rating Curve at Different Flow Rates

2016 ◽  
Vol 2 (9) ◽  
pp. 448-457 ◽  
Author(s):  
Mohammad Reza Enjilzadeh ◽  
Ebrahim Nohani
Keyword(s):  
Numerical Model ◽  
Flow Field ◽  
Numerical Modelling ◽  
Relative Error ◽  
Numerical Models ◽  
Discharge Rate ◽  
Morning Glory ◽  
Physical Models ◽  
Rating Curve ◽  
Inlet Conditions

Morning glory spillways with drop inlets are normally employed in dams built on narrow valleys or placed on steep slopes. In Iran, morning glory spillways have been commonly used in large Dam projects such as Sefidrood dam, Alborz dam, and Haraz dam. Physical models should be built to accurately determine hydraulic parameters of the flow and flow field in spillways. Establishment of a physical model involves extravagant costs and conditions that cannot be justified in some cases. Therefore, suitable numerical models can be proposed for such circumstances. Using FLOW3D numerical models, 3-dimensional numerical modelling of the flow was calibrated and validated by experimental information associated with morning glory spillway of Alborz dam and accuracy of numerical modelling was determined by relative error of numerical model. So it was attempted to determine flow pattern and control conditions of morning glory spillways in different modes using boundary conditions, inlet conditions and grid spacing of flow field and project rating curve of morning glory spillways. According to the results of numerical model, relative error of numerical modelling equals 6.4% for calculating discharge rate of the spillways. Numerical modelling error is 7.6% for determining depth parameter of the flow in spillway crest in comparison with experimental results.

scholarly journals Dynamic Response of a Single-Layer Reticulated Dome during Aircraft Impact Based on S-J Modeling Method

2019 ◽  
Vol 2019 ◽  
pp. 1-12
Author(s):  
Li Lin ◽  
Bo Huang ◽  
Yunhui Sun ◽  
Yu Zhu ◽  
Duozhi Wang
Keyword(s):  
Numerical Model ◽  
Temperature Effect ◽  
Failure Modes ◽  
Numerical Models ◽  
Material Model ◽  
Modeling Method ◽  
Dynamic Responses ◽  
Shell Structures ◽  
Large Strains ◽  
The Impact

In previous numerical models developed for the impact dynamic responses of reticulated domes, mostly BEAM 161 elements and piecewise linear plastic material model have been employed and spherical joints have been simplified as intersection points of beams, which is called the B-P method. The B-P method can be employed in studying the dynamic responses of reticulated shells under low- to moderate-speed impacts with no obvious temperature effect. However, the analysis of the dynamic responses of reticulated shells under moderate- and high-speed impacts of missiles and other aircraft using this method had errors because it could not take into account the temperature effect. To accurately describe the mechanical responses of reticulated shells under aircraft impacts, the Johnson–Cook material model considering temperature effect with corresponding SHELL 163 element was selected for determining the members of the numerical model and the shell element was used to establish the spherical joints of reticulated shells; the whole process was called the S-J modeling method. This modeling method was capable of considering the effects of high strain rates, high temperatures, large strains, stress state change, and loading history. S-J and B-P methods were used to model the reticulated shell structures. Comparing the numerical analysis results of the drop hammer impact of the two developed methods with experimental results verified the accuracy of the S-J modeling method. In addition, based on the results obtained from the S-J modeling method and LS-DYNA finite element analysis software, a numerical model was established for small aircraft impact reticulated shells and the failure modes and dynamic responses of reticulated shell structures under aircraft impacts were studied. In terms of energy analysis, it was found that the effects of roof plates, spherical joints, and temperature softening could not be ignored in such studies.

A Hybrid (Numerical-physical) Model of the Left Ventricle

2001 ◽  
Vol 24 (7) ◽  
pp. 456-462 ◽  
Author(s):  
G. Ferrari ◽  
M. Kozarski ◽  
C. De Lazzari ◽  
F. Clemente ◽  
M. Merolli ◽  
...  
Keyword(s):  
Numerical Model ◽  
Hybrid Model ◽  
Time Course ◽  
Numerical Models ◽  
Open Loop ◽  
Physical Models ◽  
Gear Pump ◽  
Arterial Tree ◽  
Pump System ◽  
Output Flow

Hydraulic models of the circulation are used to test mechanical devices and for training and research purposes; when compared to numerical models, however, they are not flexible enough and rather expensive. The solution proposed here is to merge the characteristics and the flexibility of numerical models with the functions of physical models. The result is a hybrid model with numerical and physical sections connected by an electro-hydraulic interface - which is to some extent the main problem since the numerical model can be easily changed or modified. The concept of hybrid model is applied to the representation of ventricular function by a variable elastance numerical model. This prototype is an open loop circuit and the physical section is built out of a reservoir (atrium) and a modified windkessel (arterial tree). The corresponding equations are solved numerically using the variables (atrial and arterial pressures) coming from the physical circuit. Ventricular output flow is the computed variable and is sent to a servo amplifier connected to a DC motor-gear pump system. The gear pump, behaving roughly as a flow source, is the interface to the physical circuit. Results obtained under different hemodynamic conditions demonstrate the behaviour of the ventricular model on the pressure-volume plane and the time course of output flow and arterial pressure.

scholarly journals Fixed Grid Numerical Models for Solidification and Melting of Phase Change Materials (PCMs)

2019 ◽  
Vol 9 (20) ◽  
pp. 4334 ◽  
Author(s):  
José Henrique Nazzi Ehms ◽  
Rejane De Césaro Oliveski ◽  
Luiz Alberto Oliveira Rocha ◽  
Cesare Biserni ◽  
Massimo Garai
Keyword(s):  
Numerical Model ◽  
Boundary Conditions ◽  
Phase Change ◽  
Latent Heat ◽  
Phase Change Materials ◽  
Source Term ◽  
Numerical Models ◽  
Fixed Grid ◽  
Numerical Studies ◽  
The Impact

Phase change materials (PCMs) are classified according to their phase change process, temperature, and composition. The utilization of PCMs lies mainly in the field of solar energy and building applications as well as in industrial processes. The main advantage of such materials is the use of latent heat, which allows the storage of a large amount of thermal energy with small temperature variation, improving the energy efficiency of the system. The study of PCMs using computational fluid dynamics (CFD) is widespread and has been documented in several papers, following the tendency that CFD nowadays tends to become increasingly widespread. Numerical studies of solidification and melting processes use a combination of formulations to describe the physical phenomena related to such processes, these being mainly the latent heat and the velocity transition between the liquid and the solid phases. The methods used to describe the latent heat are divided into three main groups: source term methods (E-STM), enthalpy methods (E-EM), and temperature-transforming models (E-TTM). The description of the velocity transition is, in turn, divided into three main groups: switch-off methods (SOM), source term methods (STM), and variable viscosity methods (VVM). Since a full numerical model uses a combination of at least one of the methods for each phenomenon, several combinations are possible. The main objective of the present paper was to review the numerical approaches used to describe solidification and melting processes in fixed grid models. In the first part of the present review, we focus on the PCM classification and applications, as well as analyze the main features of solidification and melting processes in different container shapes and boundary conditions. Regarding numerical models adopted in phase-change processes, the review is focused on the fixed grid methods used to describe both latent heat and velocity transition between the phases. Additionally, we discuss the most common simplifications and boundary conditions used when studying solidification and melting processes, as well as the impact of such simplifications on computational cost. Afterwards, we compare the combinations of formulations used in numerical studies of solidification and melting processes, concluding that “enthalpy–porosity” is the most widespread numerical model used in PCM studies. Moreover, several combinations of formulations are barely explored. Regarding the simulation performance, we also show a new basic method that can be employed to evaluate the computing performance in transient numerical simulations.

scholarly journals Impact of Temperature on the Moisture Buffering Performance of Palm and Sunflower Concretes

2021 ◽  
Vol 11 (12) ◽  
pp. 5420
Author(s):  
Fathia Dahir Igue ◽  
Anh Dung Tran Le ◽  
Alexandra Bourdot ◽  
Geoffrey Promis ◽  
Sy Tuan Nguyen ◽  
...  
Keyword(s):  
Numerical Model ◽  
Building Materials ◽  
Numerical Models ◽  
Buffering Capacity ◽  
Physical Models ◽  
Embodied Energy ◽  
Problem Analysis ◽  
Simulation Problem ◽  
Interesting Solution ◽  
Moisture Buffering

The use of bio-based materials (BBM) in buildings is an interesting solution as they are eco-friendly materials and have low embodied energy. This article aims to investigate the hygric performance of two bio-based materials: palm and sunflower concretes. The moisture buffering value (MBV) characterizes the ability of a material or multilayer component to moderate the variation in the indoor relative humidity (RH). In the literature, the moisture buffer values of bio-based concretes were measured at a constant temperature of 23 °C. However, in reality, the indoor temperature of the buildings is variable. The originality of this article is found in studying the influence of the temperature on the moisture buffer performance of BBM. A study at wall scale on its impact on the indoor RH at room level will be carried out. First, the physical models are presented. Second, the numerical models are implemented in the Simulation Problem Analysis and Research Kernel (SPARK) suited to complex problems. Then, the numerical model validated with the experimental results found in the literature is used to investigate the moisture buffering capacity of BBM as a function of the temperature and its application in buildings. The results show that the temperature has a significant impact on the moisture buffering capacity of bio-based building materials and its capacity to dampen indoor RH variation. Using the numerical model presented in this paper can predict and optimize the hygric performance of BBM designed for building application.

scholarly journals Assessing the influence of sea walls on the coastal vulnerability of a pinned, soft-cliff, sandy coastline

2013 ◽  
Vol 1 (1) ◽  
pp. 1127-1149 ◽  
Author(s):  
A. Barkwith ◽  
M. D. Hurst ◽  
C. W. Thomas ◽  
M. A. Ellis ◽  
P. W. Limber ◽  
...  
Keyword(s):  
Coastal Erosion ◽  
Morphological Changes ◽  
Numerical Models ◽  
Field Studies ◽  
Wave Climate ◽  
Sediment Flux ◽  
Climate Data ◽  
Coastal Morphology ◽  
Coastal Evolution ◽  
The Impact

Abstract. Coastal defences have long been employed to halt or slow coastal erosion. Their impact on local sediment flux and ecology has been studied in detail through field studies and numerical simulations. The non-local impact of a modified sediment flux regime on mesoscale erosion and accretion has received less attention. Morphological changes at this scale due to defended structures can be difficult to quantify or identify with field data. Engineering scale numerical models, often applied to assess the design of modern defences on local coastal erosion, tend not to cover large stretches of coast and are rarely applied to assess the impact of older structures. We extend previous work to explore the influences of sea walls on the evolution and morphological sensitivity of a pinned, soft-cliff, sandy coastline under a changing wave climate. The Holderness coast of East Yorkshire, UK, is used as a case study, represented both as a defended example with major sea walls included and a natural example where no sea defences exist. Using a mesoscale numerical coastal evolution model, stochastic wave climate data are perturbed gradually to assess the sensitivity of the coastal morphology to changing wave climate for both the defended and natural scenarios. Comparative analysis of the simulated output suggests that sea walls in the south of the region have a greater impact on sediment flux due to the increased sediment availability along this part of the coast. Multiple defended structures, including those separated by several kilometres, were found to interact with each other, producing a complex imprint on coastal morphology under a changing wave climate. Although spatially and temporally heterogeneous, sea walls generally slowed coastal recession and accumulated sediment on their up-drift side.

scholarly journals IRREGULAR WAVE TRANSFORMATION IN A BOUSSINESO WAVE MODEL

1986 ◽  
Vol 1 (20) ◽  
pp. 205
Author(s):  
H.H. Pruser ◽  
H. Schaper ◽  
W. Zielke
Keyword(s):  
Water Waves ◽  
Wave Equations ◽  
Numerical Models ◽  
Wave Model ◽  
Wave Climate ◽  
Irregular Waves ◽  
Wave Transformation ◽  
Diffraction Reflection ◽  
Irregular Wave ◽  
Wave Models

Numerical wave models for shallow water waves are of particular importance for the calculation of the wave climate in harbours and coastal areas. Especially nonlinear time domain models, which are based on the Boussinesq-Wave- Equations, may be helpful in the future for simulating the interaction of currents with refraction, diffraction, reflection and for simulating shoaling..-of irregular waves in natural areas; a potential which has not yet been fully developed. During the last ten years numerical models, based on these equations, have been published; such as ABBOTT et. al. , HAUGUEL and SCHAPER / ZIELKE . Research on this topic is currently being carried on. Some efforts have been made to verify the capability of the models to describe the various physical phenomena. However, up to now, verification has been limited to regular waves. The aim of this paper therefore is, to consider questions concerning irregular, nonlinear waves.

Felled Trees as a Rockfall Protection System, Experimental Study for Numerical Models Calibration

2014 ◽  
Vol 566 ◽  
pp. 449-454
Author(s):  
I. Olmedo ◽  
Franck Bourrier ◽  
D. Bertrand ◽  
Frédéric Berger ◽  
Ali Limam
Keyword(s):  
Numerical Model ◽  
Numerical Models ◽  
Contact Point ◽  
Protective Capacity ◽  
Mountain Areas ◽  
Optimal Position ◽  
Energy Forest ◽  
Device Interaction ◽  
The Impact

In mountain areas, natural hazards, such as snow avalanches, landslides and rockfall threat towns, communication routes and people. It is known that forests have a major capacity to dissipate rockfall energy. Forest maintenance or storms can reduce forest’s protective capacity; after such a reduction, felled trees can be strategically left on the slopes in order to replace live trees. The efficacy of these devices and their optimal position can be analyzed by developing a numerical model describing the rock-wooden device interaction. To develop a relevant model of these wooden devices when impacted, the research was focused, in one hand, on a rigorous characterization of the fresh wood mechanical properties to recreate the real dynamic response of stems after the impact. In the other hand, the local impactor-wood stem interaction at the contact point was analyzed. Laboratory experiments using Charpy pendulum, presented in this text, have been carried out to assess the calibration of the numerical model. Experimental results of the impact force and their relation with stems mass and the impact energy level were treated and commented. A second serie of experiments has enabled to characterize the law describing the contact between the stem and the impactor.

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