Efficient Reservoir Modelling for Flood Regulation in the Ebro River (Spain)

The vast majority of reservoirs, although built for irrigation and water supply purposes, are also used as regulation tools during floods in river basins. Thus, the selection of the most suitable model when facing the simulation of a flood wave in a combination of river reach and reservoir is not direct and frequently some analysis of the proper system of equations and the number of solved flow velocity components is needed. In this work, a stretch of the Ebro River (Spain), which is the biggest river in Spain, is simulated solving the Shallow Water Equations (SWE). The simulation model covers the area of river between the city of Zaragoza and the Mequinenza dam. The domain encompasses 721.92 km2 with 221 km of river bed, of which the last 75 km belong to the Mequinenza reservoir. The results obtained from a one-dimensional (1D) model are validated comparing with those provided by a two-dimensional (2D) model based on the same numerical scheme and with measurements. The 1D modelling loses the detail of the floodplain, but nevertheless the computational consumption is much lower compared to the 2D model with a permissible loss of accuracy. Additionally, the particular nature of this reservoir might turn the 1D model into a more suitable option. An alternative technique is applied in order to model the reservoir globally by means of a volume balance (0D) model, coupled to the 1D model of the river (1D-0D model). The results obtained are similar to those provided by the full 1D model with an improvement on computational time. Finally, an automatic regulation is implemented by means of a Proportional-Integral-Derivative (PID) algorithm and tested in both the full 1D model and the 1D-0D model. The results show that the coupled model behaves correctly even when controlled by the automatic algorithm.

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Calibration of a 1D/1D urban flood model using 1D/2D model results in the absence of field data

Water Science & Technology ◽

10.2166/wst.2011.467 ◽

2011 ◽

Vol 64 (5) ◽

pp. 1016-1024 ◽

Cited By ~ 35

Author(s):

J. Leandro ◽

S. Djordjević ◽

A. S. Chen ◽

D. A. Savić ◽

M. Stanić

Keyword(s):

Field Data ◽

Computational Time ◽

Necessary Condition ◽

Two Dimensional ◽

Time Step ◽

Urban Flood ◽

One Dimensional ◽

1D Model ◽

Surface Network ◽

2D Model

Recently increased flood events have been prompting researchers to improve existing coupled flood-models such as one-dimensional (1D)/1D and 1D/two-dimensional (2D) models. While 1D/1D models simulate sewer and surface networks using a one-dimensional approach, 1D/2D models represent the surface network by a two-dimensional surface grid. However their application raises two issues to urban flood modellers: (1) stormwater systems planning/emergency or risk analysis demands for fast models, and the 1D/2D computational time is prohibitive, (2) and the recognized lack of field data (e.g. Hunter et al. (2008)) causes difficulties for the calibration/validation of 1D/1D models. In this paper we propose to overcome these issues by calibrating a 1D/1D model with the results of a 1D/2D model. The flood-inundation results show that: (1) 1D/2D results can be used to calibrate faster 1D/1D models, (2) the 1D/1D model is able to map the 1D/2D flood maximum extent well, and the flooding limits satisfactorily in each time-step, (3) the 1D/1D model major differences are the instantaneous flow propagation and overestimation of the flood-depths within surface-ponds, (4) the agreement in the volume surcharged by both models is a necessary condition for the 1D surface-network validation and (5) the agreement of the manholes discharge shapes measures the fitness of the calibrated 1D surface-network.

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Coupling Methodology for Studying the Far Field Effects of Wave Energy Converter Arrays over a Varying Bathymetry

Energies ◽

10.3390/en11112899 ◽

2018 ◽

Vol 11 (11) ◽

pp. 2899 ◽

Cited By ~ 13

Author(s):

Gael Verao Fernandez ◽

Philip Balitsky ◽

Vasiliki Stratigaki ◽

Peter Troch

Keyword(s):

Numerical Simulations ◽

Wave Energy ◽

Near Field ◽

Coupled Model ◽

Propagation Model ◽

Irregular Waves ◽

Computational Time ◽

Far Field ◽

Field Effects ◽

Numerical Tool

For renewable wave energy to operate at grid scale, large arrays of Wave Energy Converters (WECs) need to be deployed in the ocean. Due to the hydrodynamic interactions between the individual WECs of an array, the overall power absorption and surrounding wave field will be affected, both close to the WECs (near field effects) and at large distances from their location (far field effects). Therefore, it is essential to model both the near field and far field effects of WEC arrays. It is difficult, however, to model both effects using a single numerical model that offers the desired accuracy at a reasonable computational time. The objective of this paper is to present a generic coupling methodology that will allow to model both effects accurately. The presented coupling methodology is exemplified using the mild slope wave propagation model MILDwave and the Boundary Elements Methods (BEM) solver NEMOH. NEMOH is used to model the near field effects while MILDwave is used to model the WEC array far field effects. The information between the two models is transferred using a one-way coupling. The results of the NEMOH-MILDwave coupled model are compared to the results from using only NEMOH for various test cases in uniform water depth. Additionally, the NEMOH-MILDwave coupled model is validated against available experimental wave data for a 9-WEC array. The coupling methodology proves to be a reliable numerical tool as the results demonstrate a difference between the numerical simulations results smaller than 5% and between the numerical simulations results and the experimental data ranging from 3% to 11%. The simulations are subsequently extended for a varying bathymetry, which will affect the far field effects. As a result, our coupled model proves to be a suitable numerical tool for simulating far field effects of WEC arrays for regular and irregular waves over a varying bathymetry.

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Development of RiverBox—An ArcGIS Toolbox for River Bathymetry Reconstruction

Water ◽

10.3390/w10091266 ◽

2018 ◽

Vol 10 (9) ◽

pp. 1266 ◽

Cited By ~ 7

Author(s):

Tomasz Dysarz

Keyword(s):

Cross Sections ◽

River Flow ◽

Computational Time ◽

Fully Integrated ◽

River Bed ◽

Develop Software ◽

Scripting Language ◽

Gis Environment ◽

Elevation Model ◽

Model Preparation

The main purpose of the present research is to develop software for reconstruction of the river bed on the basis of sparse cross-section measurements. The tools prepared should support the process of hydrodynamic model preparation for simulation of river flow. Considering the formats of available data and the requirements of modern modeling techniques, the prepared software is fully integrated with the GIS environment. The scripting language Python 2.7 implemented in ArcGIS 10.5.1 was chosen for this purpose. Two study cases were selected to validate and test the prepared procedures. These are stream reaches in Poland. The first is located on the Warta river, and the second on the Ner river. The data necessary for the whole procedure are: a digital elevation model, measurements of the cross-sections in the form of points, and two polyline layers representing an arbitrary river centerline and river banks. In the presented research the concept of a channel-oriented coordinate system is applied. The elevations are linearly interpolated along the longitudinal and transversal directions. The interpolation along the channel is implemented in three computational schemes linking different tools available in ArcGIS and ArcToolbox. A simplified comparison of memory usage and computational time is presented. The scheme linking longitudinal and spatial interpolation algorithms seems to be the most advantageous.

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Multiphase modeling study for storm water solids treatment in experimental storm water settling chamber

Water Science & Technology ◽

10.2166/wst.2011.638 ◽

2011 ◽

Vol 63 (12) ◽

pp. 3020-3026 ◽

Cited By ~ 1

Author(s):

Jungseok Ho

Keyword(s):

Reference Frame ◽

Particle Motion ◽

Coupled Model ◽

Storm Water ◽

Computational Time ◽

Settling Chamber ◽

Multiphase Model ◽

Coupled Models ◽

Eulerian Model ◽

Discrete Phase

This study tests four different types of multiphase models to determine the most appropriate model for predicting the behaviors of various types of storm water solids in a settling chamber. The Lagrangian reference frame discrete phase models of uncoupled and coupled models based on the interaction between the discrete phase and the continuous phase were tested. The rigid moving objects model providing six degrees of freedom particle motion was also tested to model non-spherical particle motion. The fourth model was a sediment transport model using the Eulerian reference frame model. This study tested five different storm water solids consisting of bulk, gross, coarse, sediment and fine which are classified by particle size and settling characteristics. Particle settling efficiency and computational time were considered in determining the most appropriate multiphase model. The coupled model provided better solid settling than the uncoupled model, but required 8.2% more computational time in this study. The Eulerian model matched settling efficiency for the high density finer solids. Although the Eulerian model showed reliable settling prediction, the Lagrangian coupled model can be an effective alternative requiring significantly reduced computational time.

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A Semi-Implicit Approach for Integrated Reservoir and Surface-Network Simulation

SPE Reservoir Evaluation & Engineering ◽

10.2118/163615-pa ◽

2014 ◽

Vol 17 (04) ◽

pp. 559-571 ◽

Cited By ~ 3

Author(s):

Jialing Liang ◽

Barry Rubin

Keyword(s):

Explicit Knowledge ◽

Coupled Model ◽

Network Models ◽

Computational Time ◽

New Approach ◽

Fully Implicit ◽

Implicit Approach ◽

Surface Network ◽

Well Tests ◽

Stability And Accuracy

Summary Conventionally, methods of coupling reservoirs and surface networks are categorized into implicit and explicit approaches. The term "implicit coupling" indicates that the two simulators solve unknowns together, simultaneously, or iteratively, whereas "explicit coupling" indicates that the two simulators solve unknowns sequentially and exchange their boundary conditions at the last coupled time tn. The explicit approach is straightforward to implement in existing reservoir and surface-network models and is widely used. Explicit coupling does have drawbacks, however, because well rate and pressure oscillations are often observed. In this paper, a new semi-implicit method for coupled simulation is presented. This technique stabilizes and improves the accuracy of the coupled model. The "semi-implicit coupling" overcomes the problems found in explicit-coupling methods without requiring the complexity of a fully implicit coupled model. The new approach predicts inflow-performance-relationship (IPR) curves at the next coupled time tn+1 by simultaneously conducting well tests for all wells in the reservoir before actually taking the required timestep. All wells first flow simultaneously to the next coupled time tn+1 with the well rates unchanged from the last coupled timestep. The timestep is rewound, and all well rates are reduced by a uniform fraction and then simultaneously flow again to tn+1. By extrapolating the resulting well pressures, the well's shut-in pressures at time tn+1 are determined, and thus, straight-line IPRs are produced. The new IPR curves approximate better each well's drainage region at tn+1 and each well's shut-in pressure at tn+1 which helps to stabilize the explicitly coupled model. The new coupling technique normally does not require iteration between the reservoir and surface network and normally has the stability and accuracy characteristics of an implicitly coupled approach. Because the well tests already account for individual well-drainage regions, an explicit knowledge of the well-drainage region is not required. Because of the stabilized IPR, the approach also was found to reduce the overall computational time compared with explicit coupling. Applications of the new approach are presented that show significant improvements surpassing explicit coupling in both stability and accuracy.

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Analysis of extreme flooding events through a calibrated 1D/2D coupled model: the case of Barcelona (Spain)

Journal of Hydroinformatics ◽

10.2166/hydro.2014.063 ◽

2014 ◽

Vol 17 (3) ◽

pp. 473-491 ◽

Cited By ~ 30

Author(s):

Beniamino Russo ◽

David Sunyer ◽

Marc Velasco ◽

Slobodan Djordjević

Keyword(s):

Flood Hazard ◽

Coupled Model ◽

Digital Terrain Model ◽

Early Warning Systems ◽

Computational Time ◽

Terrain Model ◽

Digital Terrain ◽

Hardware Configuration ◽

Extreme Flooding ◽

Flooding Events

This paper presents the results of a calibrated 1D/2D coupled model simulating surface and sewer flows in Barcelona. The model covers 44 km2 of the city land involving 241 km of sewers. It was developed in order to assess the flood hazard in the Raval district, historically affected by flooding during heavy rainfalls. Special attention was paid to the hydraulic characterization of the inlet systems (representing the interface between surface and underground flows), through experimental expressions used to estimate the effective runoff flows into the sewers in case of storms. A 2D unstructured mesh with more than 400,000 cells was created on the basis of a detailed digital terrain model. The model was calibrated and validated using four sets of well-recorded flooding events that occurred in 2011. The aim of this paper is to show how a detailed 1D/2D coupled model can be adequately calibrated and validated using a wide set of sewer sensors and post-event collected data (videos, photos, emergency reports, etc.). Moreover, the created model presents significant computational time savings via parallel processing and hardware configuration. Considering the computational performances achieved, the model can be used for real-time strategies and as the core of early warning systems.

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Urban pluvial flooding in Jakarta: applying state-of-the-art technology in a data scarce environment

Water Science & Technology ◽

10.2166/wst.2010.485 ◽

2010 ◽

Vol 62 (10) ◽

pp. 2246-2255 ◽

Cited By ~ 9

Author(s):

A. P. Hurford ◽

Č. Maksimović ◽

J. P. Leitão

Keyword(s):

Limited Data ◽

Rainfall Events ◽

Pluvial Flooding ◽

Urban Modelling ◽

History Of ◽

1D Model ◽

Urban Pluvial Flooding ◽

Flooding Events ◽

Heavy Rainfall Events ◽

2D Model

Available data relating to major pluvial flooding events in Jakarta, Indonesia were used to investigate the suitability of two different levels of sophistication in urban modelling tools for modelling these events. InfoWorks CS v9.0 was employed to build 1D and 1D/2D models of a 541 ha area of inner city Ciliwung River catchment which has a history of being particularly badly affected by flooding during heavy rainfall events. The study demonstrated that a 1D model was sufficient to simulate the flood extent of a major event using the limited data available. While the 1D/2D model also performed well, more data and time would have been required to match the 1D model's simulation of flood extent. Much more detailed data would have been required to produce reliable results in the 1D/2D model and to enable any kind of verification or calibration of the two models beyond visual comparison with crude flood extent maps.

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Numerical investigation of the 2d–1d structure interaction model

Mathematics and Mechanics of Solids ◽

10.1177/10812865211003330 ◽

2021 ◽

pp. 108128652110033

Author(s):

Matko Ljulj ◽

Josip Tambača

Keyword(s):

Analytical Solution ◽

Elastic Body ◽

Interaction Model ◽

Thin Body ◽

Small Thickness ◽

Structure Interaction ◽

1D Model ◽

Realistic Problem ◽

Limit Models ◽

2D Model

In this article, we explore the possibility of modeling the interaction of a 2d elastic body with a thin 2d elastic body of possibly higher thickness using a 1d model for the thin body. We use the asymptotic analysis with respect to the small thickness of the 2d interaction model and formulate five different limit models depending on the order of stiffness of the thin body with respect to the thickness. Then we formulate a 2d–1d model which has the same asymptotics as the 2d–thin 2d model with respect to thickness. Finally, we numerically test the approximation of the 2d–thin 2d model by the 2d–1d model on two problems, one with an analytical solution and one more realistic problem.

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Drag-Based Model (DBM) Tools for Forecast of Coronal Mass Ejection Arrival Time and Speed

Frontiers in Astronomy and Space Sciences ◽

10.3389/fspas.2021.639986 ◽

2021 ◽

Vol 8 ◽

Author(s):

Mateja Dumbović ◽

Jaša Čalogović ◽

Karmen Martinić ◽

Bojan Vršnak ◽

Davor Sudar ◽

...

Keyword(s):

Arrival Time ◽

Single Point ◽

Leading Edge ◽

Observational Fact ◽

1D Model ◽

Self Similar ◽

Key Aspects ◽

Mass Ejection ◽

Input Uncertainties ◽

2D Model

Forecasting the arrival time of coronal mass ejections (CMEs) and their associated shocks is one of the key aspects of space weather research. One of the commonly used models is the analytical drag-based model (DBM) for heliospheric propagation of CMEs due to its simplicity and calculation speed. The DBM relies on the observational fact that slow CMEs accelerate whereas fast CMEs decelerate and is based on the concept of magnetohydrodynamic (MHD) drag, which acts to adjust the CME speed to the ambient solar wind. Although physically DBM is applicable only to the CME magnetic structure, it is often used as a proxy for shock arrival. In recent years, the DBM equation has been used in many studies to describe the propagation of CMEs and shocks with different geometries and assumptions. In this study, we provide an overview of the five DBM versions currently available and their respective tools, developed at Hvar Observatory and frequently used by researchers and forecasters (1) basic 1D DBM, a 1D model describing the propagation of a single point (i.e., the apex of the CME) or a concentric arc (where all points propagate identically); (2) advanced 2D self-similar cone DBM, a 2D model which combines basic DBM and cone geometry describing the propagation of the CME leading edge which evolves in a self-similar manner; (3) 2D flattening cone DBM, a 2D model which combines basic DBM and cone geometry describing the propagation of the CME leading edge which does not evolve in a self-similar manner; (4) DBEM, an ensemble version of the 2D flattening cone DBM which uses CME ensembles as an input; and (5) DBEMv3, an ensemble version of the 2D flattening cone DBM which creates CME ensembles based on the input uncertainties. All five versions have been tested and published in recent years and are available online or upon request. We provide an overview of these five tools, as well as of their similarities and differences, and discuss and demonstrate their application.

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Application of the Finite Element Method to the Incremental Forming of Polymer Sheets: The Thermomechanical Coupled Model and Experimental Validations

Polymers ◽

10.3390/polym12081715 ◽

2020 ◽

Vol 12 (8) ◽

pp. 1715

Author(s):

A. García-Collado ◽

Gustavo Medina-Sanchez ◽

Munish Kumar Gupta ◽

R. Dorado-Vicente

Keyword(s):

Finite Element ◽

Numerical Solutions ◽

Incremental Forming ◽

Low Cost ◽

Single Point ◽

Approximation Error ◽

Coupled Model ◽

Element Model ◽

Computational Time ◽

Polymer Sheets

Single Point Incremental Forming (SPIF) is an innovative die-less low-cost forming method. Until now, there have not been viable numerical solutions regarding computational time and accuracy for the incremental forming of polymers. Unlike other numerical approaches, this novel work describes a coupled thermomechanical finite element model that simulates the SPIF of polymer sheets, where a simple elastoplastic constitutive equation rules the mechanical behavior. The resulting simulation attains a commitment between time and accuracy in the prediction of forming forces, generated and transmitted heat, as well as final part dimensions. An experimental test with default process parameters was used to determine an adequate numerical configuration (element type, mesh resolution, and material model). Finally, compared to a set of experimental tests with different thermoplastics, the proposed model, which does not consider complex rheological material models, shows a good agreement with an approximation error of less than 11% in the vertical forming force prediction.

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