scholarly journals Large-scale physical modelling of static liquefaction in gentle submarine slopes

Landslides ◽  
2021 ◽  
Author(s):  
Arash Maghsoudloo ◽  
Amin Askarinejad ◽  
Richard R. de Jager ◽  
Frans Molenkamp ◽  
Michael A. Hicks
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Physical Modelling ◽  
Soil Mass ◽  
University Of Technology ◽  
Static Liquefaction ◽  
Physical Model Tests ◽  
Flow Slides ◽  
Soil Instability ◽  
Soil Responses

AbstractPlanning a monitoring campaign for a natural submarine slope prone to static liquefaction is a challenging task due to the sudden nature of flow slides. Therefore, gaining a better insight by monitoring the changes in pore pressure and acceleration of the soil mass, prior to and at the onset of static liquefaction, of submerged model slopes in the laboratory, helps in quantifying the minimum required triggering levels and ultimately the development of effective margins of safety for this specific failure mechanism. This study presents a set of physical model tests of submarine flow slides in the large-scale GeoTank (GT) of Delft University of Technology, in which a tilting mechanism was employed to trigger static liquefaction in loosely packed sand layers. Novel sensors were developed to locally monitor the hydro-mechanical soil responses acting as precursors of the onset of instability. The measurements indicated that soil instability can initiate at overly gentle slope angles (6–10°) and generate significant excess pore water pressures that intensify the deformations to form a flow slide. Moreover, it was observed that the onset of instability and its propagation are highly dependent on the rate of shear stress change and the state of the soil. The obtained data can be used for the future validation of numerical models for submarine flow slides.

scholarly journals PHYSICAL MODELLING OF PROPELLER SCOUR ON AN ARMOURED SLOPE

2018 ◽  
pp. 11
Author(s):  
Neville Berard ◽  
Sundar Prasad ◽  
Brett Miller ◽  
Mathieu Deiber ◽  
Nathan Fuller
Keyword(s):  
Physical Model ◽  
Western Australia ◽  
Large Scale ◽  
Rock Slope ◽  
Physical Modelling ◽  
Concrete Block ◽  
Model Tests ◽  
Initial Assessment ◽  
Deep Basin ◽  
Physical Model Tests

CITIC Pacific Mining (CPM) is proposing to increase throughput at their existing Sino Iron Terminal in Cape Preston, Western Australia, using self-propelled Handysize transshipment shuttle vessels (TSV) instead of dumb barges. Initial assessment using various desktop methods (PIANC, 2015) indicated that the armoured rock slope adjacent to the berth face would incur damage due to wash from the vessel side thrusters and the main propeller. Large scale (13.5:1) physical model tests were undertaken in a 6 m x 15 m x 1.4 m deep basin at UNSW to measure wash velocity and armour stability. The physical modelling demonstrated that the rock slope was more stable than expected, but that some armour was mobilized. Additional tests were also completed to investigate the efficacy of Articulated Concrete Block Mattresses (ACMs) to protect the rock slope from propeller wash.

scholarly journals Research Progress of Initial Mechanism on Debris Flow and Related Discrimination Methods: A Review

2021 ◽  
Vol 9 ◽  
Author(s):  
Jun Du ◽  
Zhong-jie Fan ◽  
Wen-tao Xu ◽  
Lin-yao Dong
Keyword(s):  
Debris Flow ◽  
Large Scale ◽  
Numerical Models ◽  
Soil Mass ◽  
Assessment Method ◽  
Research Progress ◽  
Two Phase ◽  
Indicator Method ◽  
Technical Limitation ◽  
Debris Flow Initiation

The initial of debris flow can be classified into two types based on their triggering positions, that is, debris flow from slope and debris flow from gully or channel. For the former, great progress has been achieved on the mechanisms of soil failure and liquefaction. The framework established by a series of theories or laws, such as the Mohr–Coulomb criteria, the unsaturated soil mechanics, and the critical state of soil mass, has been used widely in industry and research. However, the details and discrimination basis for the transformation process from landslide into debris flow still need to be further clarified. Relatively, debris flow from gully or channel is more complex due to its various mass sources and the diversity of processes. Nevertheless, through a great number of case studies and experimental statistics, people have gradually recognized the influential rule and critical condition of factors from landform, hydrology, and other aspects on debris flow initiation. Furthermore, based on the theories of granular flow, continuum mechanics, and rheological law, some typical event-based scenarios can also be reproduced by different single-/two-phase depth integral/average numerical models. However, some key knowledge on mechanism and application level is still insufficient, such as the erosion and entrainment mechanism of materials from different sources, the boundary tractions and materials exchange, as well as the selection of prediction indicators. Three current discriminated methodologies for debris flow initiation, that is, the safety factor method, the rainfall indicator method, and the comprehensive assessment method, were summarized in this article. Considering the technical limitation of each methodology, it is believed that the establishment or improvement of a unified, stable, and open-access database system for event registration and query, as well as the development of large-scale and high-precision rainfall monitoring, is still regarded as the important aspect of debris flow prevention in the future. In addition, as an economic and efficiency means for obtaining information on potential threats and real-time hazard messages, the multielement method for debris flow is recommended as a long-term reference.

scholarly journals Vanadium Redox Flow Batteries: A Review Oriented to Fluid-Dynamic Optimization

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 176
Author(s):  
Iñigo Aramendia ◽  
Unai Fernandez-Gamiz ◽  
Adrian Martinez-San-Vicente ◽  
Ekaitz Zulueta ◽  
Jose Manuel Lopez-Guede
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Renewable Energy Sources ◽  
Vanadium Redox Flow Battery ◽  
Redox Flow Batteries ◽  
Design Flexibility ◽  
Flow Batteries ◽  
Exchange Membrane ◽  
Vanadium Redox

Large-scale energy storage systems (ESS) are nowadays growing in popularity due to the increase in the energy production by renewable energy sources, which in general have a random intermittent nature. Currently, several redox flow batteries have been presented as an alternative of the classical ESS; the scalability, design flexibility and long life cycle of the vanadium redox flow battery (VRFB) have made it to stand out. In a VRFB cell, which consists of two electrodes and an ion exchange membrane, the electrolyte flows through the electrodes where the electrochemical reactions take place. Computational Fluid Dynamics (CFD) simulations are a very powerful tool to develop feasible numerical models to enhance the performance and lifetime of VRFBs. This review aims to present and discuss the numerical models developed in this field and, particularly, to analyze different types of flow fields and patterns that can be found in the literature. The numerical studies presented in this review are a helpful tool to evaluate several key parameters important to optimize the energy systems based on redox flow technologies.

scholarly journals Process-Based Model Prediction of Coastal Dune Erosion through Parametric Calibration

2021 ◽  
Vol 9 (6) ◽  
pp. 635
Author(s):  
Hyeok Jin ◽  
Kideok Do ◽  
Sungwon Shin ◽  
Daniel Cox
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Model Performance ◽  
Coastal Dunes ◽  
Wave Transformation ◽  
Storm Event ◽  
Face Model ◽  
Dune Erosion ◽  
Simulation Performance ◽  
Sand Bar

Coastal dunes are important morphological features for both ecosystems and coastal hazard mitigation. Because understanding and predicting dune erosion phenomena is very important, various numerical models have been developed to improve the accuracy. In the present study, a process-based model (XBeachX) was tested and calibrated to improve the accuracy of the simulation of dune erosion from a storm event by adjusting the coefficients in the model and comparing it with the large-scale experimental data. The breaker slope coefficient was calibrated to predict cross-shore wave transformation more accurately. To improve the prediction of the dune erosion profile, the coefficients related to skewness and asymmetry were adjusted. Moreover, the bermslope coefficient was calibrated to improve the simulation performance of the bermslope near the dune face. Model performance was assessed based on the model-data comparisons. The calibrated XBeachX successfully predicted wave transformation and dune erosion phenomena. In addition, the results obtained from other two similar experiments on dune erosion with the same calibrated set matched well with the observed wave and profile data. However, the prediction of underwater sand bar evolution remains a challenge.

Coupled Thermo-Hydro-Geochemical Models of Engineered Barrier Systems: The Febex Project

2000 ◽  
Vol 663 ◽  
Author(s):  
J. Samper ◽  
R. Juncosa ◽  
V. Navarro ◽  
J. Delgado ◽  
L. Montenegro ◽  
...  
Keyword(s):  
Large Scale ◽  
Reference Model ◽  
Numerical Models ◽  
Full Scale ◽  
Small Scale ◽  
Model Parameters ◽  
In Situ Test ◽  
Wide Range ◽  
Engineered Barrier

ABSTRACTFEBEX (Full-scale Engineered Barrier EXperiment) is a demonstration and research project dealing with the bentonite engineered barrier designed for sealing and containment of waste in a high level radioactive waste repository (HLWR). It includes two main experiments: an situ full-scale test performed at Grimsel (GTS) and a mock-up test operating since February 1997 at CIEMAT facilities in Madrid (Spain) [1,2,3]. One of the objectives of FEBEX is the development and testing of conceptual and numerical models for the thermal, hydrodynamic, and geochemical (THG) processes expected to take place in engineered clay barriers. A significant improvement in coupled THG modeling of the clay barrier has been achieved both in terms of a better understanding of THG processes and more sophisticated THG computer codes. The ability of these models to reproduce the observed THG patterns in a wide range of THG conditions enhances the confidence in their prediction capabilities. Numerical THG models of heating and hydration experiments performed on small-scale lab cells provide excellent results for temperatures, water inflow and final water content in the cells [3]. Calculated concentrations at the end of the experiments reproduce most of the patterns of measured data. In general, the fit of concentrations of dissolved species is better than that of exchanged cations. These models were later used to simulate the evolution of the large-scale experiments (in situ and mock-up). Some thermo-hydrodynamic hypotheses and bentonite parameters were slightly revised during TH calibration of the mock-up test. The results of the reference model reproduce simultaneously the observed water inflows and bentonite temperatures and relative humidities. Although the model is highly sensitive to one-at-a-time variations in model parameters, the possibility of parameter combinations leading to similar fits cannot be precluded. The TH model of the “in situ” test is based on the same bentonite TH parameters and assumptions as for the “mock-up” test. Granite parameters were slightly modified during the calibration process in order to reproduce the observed thermal and hydrodynamic evolution. The reference model captures properly relative humidities and temperatures in the bentonite [3]. It also reproduces the observed spatial distribution of water pressures and temperatures in the granite. Once calibrated the TH aspects of the model, predictions of the THG evolution of both tests were performed. Data from the dismantling of the in situ test, which is planned for the summer of 2001, will provide a unique opportunity to test and validate current THG models of the EBS.

Innovative Volumetric Solar Receiver Micro-Design Based on Numerical Predictions

2015 ◽  
Author(s):  
Raffaele Capuano ◽  
Thomas Fend ◽  
Bernhard Hoffschmidt ◽  
Robert Pitz-Paal
Keyword(s):  
Solar Radiation ◽  
Energy Demand ◽  
Large Scale ◽  
Solar Power ◽  
Numerical Models ◽  
Numerical Predictions ◽  
Proper Design ◽  
Global Increase ◽  
Solar Power Tower ◽  
Solar Receiver

Due to the continuous global increase in energy demand, Concentrated Solar Power (CSP) represents an excellent alternative, or add-on to existing systems for the production of energy on a large scale. In some of these systems, the Solar Power Tower plants (SPT), the conversion of solar radiation into heat occurs in certain components defined as solar receivers, placed in correspondence of the focus of the reflected sunlight. In a particular type of solar receivers, defined as volumetric, the use of porous materials is foreseen. These receivers are characterized by a porous structure called absorber. The latter, hit by the reflected solar radiation, transfers the heat to the evolving fluid, generally air subject to natural convection. The proper design of these elements is essential in order to achieve high efficiencies, making such structures extremely beneficial for the overall performances of the energy production process. In the following study, a parametric analysis and an optimized characterization of the structure have been performed with the use of self-developed numerical models. The knowledge and results gained through this study have been used to define an optimization path in order to improve the absorber microstructure, starting from the current in-house state-of-the-art technology until obtaining a new advanced geometry.

scholarly journals A general Cluster data and global MHD simulation comparison

2008 ◽  
Vol 26 (11) ◽  
pp. 3411-3428 ◽  
Author(s):  
P. Daum ◽  
M. H. Denton ◽  
J. A. Wild ◽  
M. G. G. T. Taylor ◽  
J. Šafránková ◽  
...  
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Mhd Simulation ◽  
Global Context ◽  
Cluster Data ◽  
Verification Methods ◽  
Modelling Studies ◽  
Global Mhd Simulation ◽  
The Many

Abstract. Among the many challenges facing the space weather modelling community today, is the need for validation and verification methods of the numerical models available describing the complex nonlinear Sun-Earth system. Magnetohydrodynamic (MHD) models represent the latest numerical models of this environment and have the unique ability to span the enormous distances present in the magnetosphere, from several hundred kilometres to several thousand kilometres above the Earth's surface. This makes it especially difficult to develop verification and validation methods which posses the same range spans as the models. In this paper we present a first general large-scale comparison between four years (2001–2004) worth of in situ Cluster plasma observations and the corresponding simulated predictions from the coupled Block-Adaptive-Tree-Solarwind-Roe-Upwind-Scheme (BATS-R-US) MHD code. The comparison between the in situ measurements and the model predictions reveals that by systematically constraining the MHD model inflow boundary conditions a good correlation between the in situ observations and the modeled data can be found. These results have an implication for modelling studies addressing also smaller scale features of the magnetosphere. The global MHD simulation can therefore be used to place localised satellite and/or ground-based observations into a global context and fill the gaps left by measurements.

scholarly journals PORT RESONANCE MITIGATION MODELED INTRODUCING ARJ-R STRUCTURES

2020 ◽  
pp. 38
Author(s):  
Jose A. GONZALEZ-ESCRIVA ◽  
Josep R. MEDINA ◽  
Joaquin M. GARRIDO
Keyword(s):  
Reflection Coefficient ◽  
Physical Model ◽  
Large Scale ◽  
Low Frequency ◽  
Model Tests ◽  
Wave Interference ◽  
Low Frequency Oscillations ◽  
Physical Model Tests ◽  
Similar Cost ◽  
Interference Mechanism

ARJ-R caissons are based on the "long-circuit" concept (Medina et al, 2016) that allows the extension of the destructive wave interference mechanism to mitigate low frequency oscillations without enlarging the width of the caisson. The performance of the ARJ-R caissons is referred to its reflection coefficient (Cr) which was obtained through large-scale physical model tests (Gonzalez-Escriva et al, 2018). In this paper, the effectiveness of Anti-Reflective Jarlan-type structures for Port Resonance mitigation (ARJ-R) has been assessed numerically for the port of Denia (Spain). ARJ-R structures are constructible, with similar dimensions as conventional vertical quay caissons and with a similar cost (15percent more than conventional vertical caisson).Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/LomQEVpvjik

scholarly journals LARGE AND SMALL SCALE WAVE OVERTOPPING MEASUREMENTS FOR AFSLUITDIJK REHABILITATION PROJECT

2020 ◽  
pp. 15
Author(s):  
Wouter Ockeloen ◽  
Coen Kuiper ◽  
Sjoerd van den Steen
Keyword(s):  
Water Management ◽  
Physical Model ◽  
Large Scale ◽  
Wadden Sea ◽  
Model Tests ◽  
Small Scale ◽  
Water Safety ◽  
Wave Overtopping ◽  
Physical Model Tests ◽  
Large Scale Tests

The 'Afsluitdijk' is a 32 km enclosure dam which separates the Wadden sea and the Lake IJssel. The dam currently undergoes a major rehabilitation to meet the requirements with regard to water safety. The Dutch Ministry of infrastructure and Water Management (Rijkswaterstaat division) has commissioned Levvel, a consortium of BAM, Van Oord and Rebel, to prepare the design and carry out the reconstruction of the dam including sluices and highway. The project includes reinforcement of the armour layers and wave overtopping reduction. As part of the contract Rijkswaterstaat prescribed the contractor (Levvel) to verify the design with large scale physical model tests (min. 1:3 scale). These tests were carried out in the Delta Flume of Deltares. Prior to the large scale tests, smaller scale tests (1:20) have been carried out to optimize the design with regard to armour stability and wave overtopping. The research described here focuses on the wave overtopping.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/kPga0wVCCIE

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