The majority of software for groundwater modeling is based on finite difference and finite element methods. In 2013, the United States Geological Survey ( USGS) released a new version of MODFLOW, called MODFLOW-USG, in order to support UnStructured Grids. Soon enough, graphical user interface (GUI ) provided the new version of Groundwater Vistas (ver. 6) in order to support MODFLOW-USG software packages. In the first part of this thesis, a study area, previously modeled using a structured version of MODFLOW (i.e. MODFLOW2000), is developed in MODFLOW-USG in order to evaluate its new features and capabilities in comparison with the older version. In the second part of the study, MODFLOW-USG is applied to another study area, previously modeled with MODFLOW-2005, in order to simulate the transport of heat through a borehole heat exchanger using the new transport package provided by MODFLOW-USG and make a comparison with the results obtained through MODFLOW-2005. Different approaches for the grid design and the u-pipe representation are applied for finding the best possible solution. The results of the comparisons between structured and unstructured versions of MODFLOW show that for simple problems (as the one of the first part of this study), MODFLOW-USG could provide flexibility in grid design resulting in fewer grid cells and consequent faster running process. However, the second part of this study, where a very refined grid is required due to the complexity of the problemMODFLOW-USG turns out to be not able to provide the correct results with an unstructured grid, while the grid generation is still better with MODFLOW-USG.
La maggior parte del software per la modellizazione delle acque sotterranee si basa sui metodi di differenze ed elementi finiti. Nel 2013, lo United States Geological Survey ha rilasciato una nuova versione di MODFLOW, chiamata MODFLOW-USG, al fine di supportare le griglie non strutturate. Graphical user interface (GUI ) ha fornito la nuova versione di Groundwater Vistas (versione 6) per supportare i pacchetti software MODFLOW-USG. Nella prima parte di questa tesi, un'area di studio, precedentemente modellata utilizzando una versione strutturata di MODFLOW (MODFLOW2000), è sviluppata in MODFLOW-USG per valutare le nuove funzionalità rispetto alla versione precedente. Nella seconda parte dello studio, MODFLOW-USG è applicato a un'altra area di interesse, precedentemente modellata con MODFLOW-2005, per simulare il trasporto di calore attraverso uno borehole heat exchanger utilizzando il nuovo pacchetto di trasporto fornito da MODFLOW-USG e fare un confronto con i risultati ottenuti attraverso MODFLOW-2005. Diversi approcci per la progettazione della griglia e la rappresentazione della U-pipe vengono applicati per trovare la migliore soluzione possibile. I risultati dei confronti tra versioni strutturate e non strutturate di MODFLOW mostrano che per problemi semplici come quello della prima parte di questo studio, MODFLOW-USG potrebbe fornire flessibilità nella progettazione della griglia con conseguente riduzione delle celle della griglia ed un conseguente processo di esecuzione più veloce. Tuttavia, la seconda parte di questo studio, dove è richiesta una griglia molto raffinata a causa della complessità del problema MODFLOW-USG risulta essere in grado di fornire risultati corretti con una griglia non strutturata, mentre la generazione della rete è ancora migliore con MODFLOW-USG.
An evaluation of MODFLOW-USG
FALAKDIN, PARISA
2017/2018
Abstract
The majority of software for groundwater modeling is based on finite difference and finite element methods. In 2013, the United States Geological Survey ( USGS) released a new version of MODFLOW, called MODFLOW-USG, in order to support UnStructured Grids. Soon enough, graphical user interface (GUI ) provided the new version of Groundwater Vistas (ver. 6) in order to support MODFLOW-USG software packages. In the first part of this thesis, a study area, previously modeled using a structured version of MODFLOW (i.e. MODFLOW2000), is developed in MODFLOW-USG in order to evaluate its new features and capabilities in comparison with the older version. In the second part of the study, MODFLOW-USG is applied to another study area, previously modeled with MODFLOW-2005, in order to simulate the transport of heat through a borehole heat exchanger using the new transport package provided by MODFLOW-USG and make a comparison with the results obtained through MODFLOW-2005. Different approaches for the grid design and the u-pipe representation are applied for finding the best possible solution. The results of the comparisons between structured and unstructured versions of MODFLOW show that for simple problems (as the one of the first part of this study), MODFLOW-USG could provide flexibility in grid design resulting in fewer grid cells and consequent faster running process. However, the second part of this study, where a very refined grid is required due to the complexity of the problemMODFLOW-USG turns out to be not able to provide the correct results with an unstructured grid, while the grid generation is still better with MODFLOW-USG.| File | Dimensione | Formato | |
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Final.pdf
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Descrizione: Evaluation of the accuracy and efficiency of the new features and advancement in MODFLOW-USG.
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https://hdl.handle.net/10589/146440