scholarly journals Decomposition technique for contributions to groundwater heads from inside and outside of an arbitrary boundary: Application to Guantao County, North China Plain

2019 ◽  
Author(s):  
Ning Li ◽  
Wolfgang Kinzelbach ◽  
Haitao Li ◽  
Wenpeng Li ◽  
Fei Chen
Keyword(s):  
Boundary Conditions ◽  
Numerical Models ◽  
Soil Column ◽  
Scale Model ◽  
Small Scale ◽  
Decomposition Technique ◽  
Arbitrary Boundary ◽  
Groundwater Head ◽  
Administrative Unit ◽  
Small Models

Abstract. To assess the efficiency of groundwater management of an administrative unit, we propose to decompose the groundwater head changes within an administrative unit into inside and outside contributions by using numerical models. Guantao County of Hebei Province, China, serves as an example to demonstrate the decomposition technique. The groundwater flow model of Guantao was constructed using observed heads as prescribed head boundary conditions. The model was coupled with Hydrus 1D, to calculate the groundwater recharge distribution in time reflecting the delay and damping effects of the soil column on seepage at the surface. The model was calibrated by adjusting parameters such as hydraulic conductivities, recharge infiltration ratios and specific yields. The calibrated parameters are then used in a large model with a boundary at large distance from Guantao administrative boundary to determine the groundwater head changes due to inside drivers. The differences of the two models on the Guantao boundary serve as the specified head values on the boundary for a small scale model, which is used to calculate the groundwater head imposed by outside drivers. To eliminate inconsistencies caused by the different types of boundary conditions of large and small models, the groundwater head changes due to inside drivers must be updated. The results indicate that the groundwater head changes in the centre and south of Guantao County are influenced equally by both inside and outside contributions, while in the north outside contributions have the stronger impact. The sensitivity analysis shows that the groundwater head changes and their decomposition are much more sensitive to infiltration ratios than to the aquifer parameters. The parameters within Guantao have a certain influence on the net groundwater head changes while the parameters outside of Guantao have only an influence on the decomposition.

scholarly journals Decomposition technique for contributions to groundwater heads from inside and outside of an arbitrary boundary: application to Guantao County, North China Plain

2019 ◽  
Vol 23 (7) ◽  
pp. 2823-2840 ◽  
Author(s):  
Ning Li ◽  
Wolfgang Kinzelbach ◽  
Haitao Li ◽  
Wenpeng Li ◽  
Fei Chen
Keyword(s):  
Boundary Conditions ◽  
Numerical Models ◽  
Soil Column ◽  
Scale Model ◽  
Small Scale ◽  
Decomposition Technique ◽  
Arbitrary Boundary ◽  
Groundwater Head ◽  
Administrative Unit ◽  
Small Models

Abstract. To assess the efficiency of the groundwater management of an administrative unit, we propose decomposing the groundwater head changes within an administrative unit into inside and outside contributions by using numerical models. Guantao County of Hebei Province, China, serves as an example to demonstrate the decomposition technique. The groundwater flow model of Guantao was constructed using observed heads as prescribed head boundary conditions. The model was coupled with Hydrus 1-D to calculate the groundwater recharge distribution in time reflecting the delay and damping effects of the soil column on seepage at the surface. The model was calibrated by adjusting parameters such as hydraulic conductivities, recharge infiltration ratios and specific yields. The calibrated parameters are then used in a large model with a boundary at a large distance from Guantao administrative boundary to determine the groundwater head changes due to inside drivers. The differences of the two models on the Guantao boundary serve as the specified head values on the boundary for a small-scale model, which is used to calculate the groundwater head imposed by outside drivers. To eliminate inconsistencies caused by the different types of boundary conditions of large and small models, the groundwater head changes due to inside drivers must be updated. The results indicate that the groundwater head changes in the center and south of Guantao County are influenced equally by both inside and outside contributions, while in the north outside contributions have the stronger impact. On average, 48.5 % of groundwater head changes in the whole of Guantao County is influenced by inside contributions, while 51.5 % is due to outside contributions. The sensitivity analysis shows that the groundwater head changes and their decomposition are much more sensitive to infiltration ratios than to the aquifer parameters. The parameters within Guantao have a certain influence on the net groundwater head changes, while the parameters outside of Guantao only have an influence on the decomposition.

scholarly journals Design of a Small-Scale Experimental Model of the International Space Station Crew Quarters for a PIV Flow Field Study

2019 ◽  
Vol 111 ◽  
pp. 01045
Author(s):  
Matei-Razvan Georgescu ◽  
Ilinca Nastase ◽  
Amina Meslem ◽  
Mihnea Sandu ◽  
Florin Bode
Keyword(s):  
International Space Station ◽  
Numerical Models ◽  
Space Station ◽  
Scale Model ◽  
Microgravity Environment ◽  
Small Scale ◽  
Piv Measurements ◽  
International Space ◽  
The Subject ◽  
Small Scale Model

An attempt at improving the ventilation solution for the crew quarters aboard the International Space Station requires a thorough understanding of the flow dynamics in a microgravity environment. An experimental study is required in order to validate the numerical models. As part of this process, a small-scale model was proposed for a detailed study of the velocity field. PIV measurements in water offer high quality results and were chosen for the subject. Following certain similitude criteria, an equivalence can be found between the results of these measurements and the real ventilation scenario. This paper describes the development process of this small-scale model as well as its performance in the initial test runs. Details regarding the advantages and weaknesses of this first model are the core of the paper, with the intention of aiding researchers in their design of similar models. The conclusion presents future steps and proposed improvements to the model.

scholarly journals CEOHYDRAULIC INVESTIGATIONS OF RUBBLE MOUND BREAKWATERS

1988 ◽  
Vol 1 (21) ◽  
pp. 166 ◽  
Author(s):  
W. Burger ◽  
H. Oumeraci ◽  
H.W. Partenscky
Keyword(s):  
Pore Pressure ◽  
Scale Effects ◽  
Numerical Models ◽  
Model Tests ◽  
Physical Models ◽  
Core Material ◽  
Scale Model ◽  
Small Scale ◽  
Rubble Mound ◽  
Rubble Mound Breakwaters

Due to the increase of ship sizes in recent decades a number of harbours and terminals have been built in deeper waters. Accordingly, the structures which have to provide protection against wave action become higher, too. In most cases, these protective structures are of the rubble mound type. Under such conditions the flow induced by waves within the breakwater and the related geotechnical behaviour of the rubble mound fill become more significant fcr the overall stability and should be considered in the design. In addition, it is known that the scales usually adopted in hydraulic models (1:30 to 1:60) for investigating the stability of large rubble mound breakwaters generally lead to scale effects with respect to the flow field inside the breakwater. This means that small-scale model tests are not appropriate for investigating the internal flow patterns or for evaluating the pore pressure field induced by the incident waves in,the core material. because of the uncontrolled conditions in the prototype, and since the actual permeability of the prototype rubble mound fill cannot be predicted (segregation, settlement, variation in grading, etc.), the use of large-scale physical models seems to be the most promising method for basic investigations of this kind. Moreover, the results of such largescale model tests may be used to validate the usual smaller scale models and to calibrate numerical models. Therefore, it is one of the objectives of our research programme on rubble mound breakwaters, which started in 1987, to concentrate on the evaluation of the wave-induced flow and pore pressure distribution within the breakwater.

scholarly journals An Integrated Modeling Scheme For Characterizing 3D Hydrogeological Heterogeneity of The New Jersey Shelf

2021 ◽  
Author(s):  
Ariel Tremayne Thomas ◽  
Jan von Harten ◽  
Tomi Adriansyah Jusri ◽  
Sönke Reiche ◽  
Florian Wellmann
Keyword(s):  
New Jersey ◽  
Large Scale ◽  
Numerical Models ◽  
Integrated Approach ◽  
Scale Model ◽  
Small Scale ◽  
Gaussian Field ◽  
Seismic Profiles ◽  
Borehole Data ◽  
Shelf Wave

Abstract Continental shelves around the globe are hosts to vast reservoirs of offshore freshened groundwater. These systems show considerable complexity, often as a function of the geological heterogeneity. Data needed to characterise these systems are often sparse, and numerical models rely on generalized simplifications of the geological environment. In order to improve our understanding of these systems, it is necessary to implement modeling approaches that can produce large-scale geologically representative models using sparse data. We present an interdisciplinary stochastic modeling workflow incorporating borehole data, 2D depth-migrated seismic profiles, seismic attributes, and prior knowledge of the depositional setting. We generate a conditioned Gaussian field of porosity on the New Jersey shelf. We also perform a petrophysical conversion to a corresponding permeability distribution. The model dimensions are 134 km x 69 km x 1.7 km, with an adjustable resolution that can be adapted for process-based models of flow and solute transport. The integrated approach successfully translates small-scale porosity variations to a shelf-scale model that honors key characteristics of the New Jersey shelf wave-dominated depositional environment. The model was generated using open-source packages. All data and code to reproduce the complete workflow are provided along with this study so the model can be reproduced at any resolution for further studies of continental shelf processes offshore New Jersey.

scholarly journals CHALLENGES OF BOUNDARY CONDITIONS IN OPEN OCEAN MODELS

2020 ◽  
pp. 52
Author(s):  
Judith Herold ◽  
Eric Lemont ◽  
Stuart Bettington ◽  
Edward Couriel
Keyword(s):  
Environmental Impact ◽  
Boundary Conditions ◽  
Large Scale ◽  
Numerical Models ◽  
Open Ocean ◽  
Small Scale ◽  
Ocean Models ◽  
Support Engineering ◽  
Ocean Boundary ◽  
Professional Judgement

The development and calibration of coastal numerical models to support engineering design and environmental impact studies is a challenging process and one that requires professional judgement and continual assessment of all aspects of the model makeup. Fundamental to the integrity of the model are appropriate boundary conditions and quality observational data for calibration. Open ocean boundary conditions are typically the most complex and important aspect of a model build. They represent the influence of dynamics occurring beyond the model extent, bridging large-scale dynamics to the small-scale processes in the model. This study discusses the challenges of open ocean boundaries and how we utilised data to achieve an effective model.Recorded Presentation from the vICCE (YouTube Link): https://youtu.be/evL7f_17wZg

Dynamic Response Analysis of Harbor Caisson Structure Under Various Boundary Conditions

2009 ◽  
Author(s):  
Jeong-Tae Kim ◽  
So-Young Lee ◽  
Dong-Soo Hong ◽  
Jin-Hak Yi ◽  
Yoon-Koo Kang
Keyword(s):  
Boundary Conditions ◽  
Frequency Response ◽  
Experimental Tests ◽  
Element Model ◽  
Dynamic Responses ◽  
Scale Model ◽  
Small Scale ◽  
Response Analysis ◽  
Fundamental Study ◽  
Various Boundary Conditions

In this study, vibration responses of harbor caisson structures with various boundary conditions are experimentally examined as a fundamental study to develop a health assessment technique for harbor structures. To achieve the objective, four-step approach is implemented. Firstly, a target caisson structure is selected and a small-scale model of the caisson model is constructed in the laboratory. Secondly, a finite element model of the caisson model is generated to analyze dynamic responses of the structure. Thirdly, experimental tests are performed on the caisson model to obtain dynamic responses under various boundary conditions and impact locations. Four different boundary conditions, 1) ‘hanging by crane’, 2) ‘standing on styrofoam block’, 3) ‘standing on sand mat’, and 4) ‘standing on concrete floor’ are considered. Finally, variation of frequency response ratio assurance criterion and correlation coefficients of frequency response functions are analyzed.

scholarly journals Development and Validation of Numerical Models for Evaluation of Foam-Vacuum Insulation Panel Composite Boards, Including Edge Effects

Energies ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 2228 ◽  
Author(s):  
Kaushik Biswas
Keyword(s):  
Boundary Conditions ◽  
Large Scale ◽  
Numerical Models ◽  
Small Scale ◽  
Minimization Method ◽  
Element Analysis ◽  
Vacuum Insulation ◽  
Experimental Parameters ◽  
Development And Validation ◽  
Vacuum Insulation Panel

A combined finite element analysis (FEA) and experimental validation approach to estimating effective edge conductivities of vacuum insulation panels (VIPs) embedded in foam-VIP composites is presented. The edge conductivities were estimated by comparing the simulation results with measurements of small-scale (0.61 × 0.61 m) foam-VIP composites and using an error minimization method. The two composites contained multiple VIPs that were butt-jointed with each other in one composite and separated by foam insulation in the other. Edge conductivities were estimated by considering the neighboring materials, i.e., whether the VIPs were adjacent to other VIPs or foam insulation. Models incorporating the edge conductivities were then used to simulate additional small- and large-scale (2.44 × 1.22 m) composites for validation and evaluation of the overall thermal transmission properties. The simulations used either the same boundary conditions as the experiments or used the experimental parameters to define the appropriate boundary conditions.

Numerical, Experimental and Analytical Investigation of the Mass Outflow From a Pickling Tank

2004 ◽  
Author(s):  
Andreas Mehrle ◽  
Philipp Gittler ◽  
Mirko Javurek ◽  
Andreas Osterkorn
Keyword(s):  
Free Surface ◽  
Boundary Conditions ◽  
Scale Model ◽  
Small Scale ◽  
Intermediate Step ◽  
Order Of Growth ◽  
Cfd Simulations ◽  
Strip Surface ◽  
Vof Model ◽  
Mass Outflow

The process of pickling is an important intermediate step in the production line of steel processing. The strip surface is cleaned from grease and scales before further processing by immersion into an acid bath. Problems arising at higher process speeds with increasing inclination of the free surface are reduced strip immersion length and increased mass outflow. In this paper a differential equation is derived describing the influence of the bath depth on the local surface inclination for a simplified two-dimensional case. Since it can only be solved analytically for trivial boundary conditions a numerical solution has been computed giving an estimation for the order of growth of the bath inclination and mass outflow with the strip velocity. Further, a series of CFD simulations of the complete three-dimensional geometry at different strip velocities have been carried out calibrating the formulas of mass outflow. In the course of the CFD simulations the deformation of the free surface was calculated by a VOF model with explicit reconstruction of the interface. A standard κ–ε turbulence model was applied and special considerations have been made regarding the boundary conditions. Finally the resulting formula has been verified making use of data from a small scale model. It was found that the overflow at the far end of the tank is the dominant mass transfer mechanism at process velocities of the current generation of pickling tanks. Still, due to the superior order of growth, mass drag-out via the upper side of the strip becomes important for process velocities of 8 to 10 m/s. The good accordance of the analytical solution, CFD simulation and experiment indicate that the formula derived in the first part of the paper is a good estimation for the mass outflow from the pickling tank, hence making time and resource consuming CFD simulations obsolete for the design layout. Further the validity of geometrically non similar small scale models could be showed.

Multi-scale characterization and modelling of damage evolution in nuclear Gilsocarbon graphite

2015 ◽  
Vol 1809 ◽  
pp. 1-6 ◽  
Author(s):  
Dong Liu ◽  
Peter Heard ◽  
Branko Šavija ◽  
Gillian Smith ◽  
Erik Schlangen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Mechanical Testing ◽  
Numerical Models ◽  
Ion Beam ◽  
Microstructural Characterization ◽  
Scale Model ◽  
Small Scale ◽  
Length Scale ◽  
Multi Scale ◽  
Scale Characterization

ABSTRACTIn the present work, the microstructure and mechanical properties of Gilsocarbon graphite have been characterized over a range of length-scales. Optical imaging, combined with 3D X-ray computed tomography and 3D high-resolution tomography based on focus ion beam milling has been adopted for microstructural characterization. A range of small-scale mechanical testing approaches are applied including an in situ micro-cantilever technique based in a Dualbeam workstation. It was found that pores ranging in size from nanometers to tens of micrometers in diameter are present which modify the deformation and fracture characteristics of the material. This multi-scale mechanical testing approach revealed the significant change of mechanical properties, for example flexural strength, of this graphite over the length-scale from a micrometer to tens of centimeters. Such differences emphasize why input parameters to numerical models have to be undertaken at the appropriate length-scale to allow predictions of the deformation, fracture and the stochastic features of the strength of the graphite with the required confidence. Finally, the results from a multi-scale model demonstrated that these data derived from the micro-scale tests can be extrapolated, with high confidence, to large components with realistic dimensions.

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