Littérature scientifique sur le sujet « Software Feflow »

The OpenMI standard defines an interface that allows time-dependent models to exchange data at runtime. The migration of a flow simulation programme to OpenMI compliance usually requires changes in the source code or even a reorganisation of the programme sequence. Users of commercial flow simulation programmes depend on the software producer if they want to couple their models according to the OpenMI standard. We describe how we made the groundwater flow simulation programme Feflow OpenMI compliant without changing the source code: an OpenMI-compliant control application communicates with Feflow via remote procedure calls. A basic prerequisite for applying this method is an entry point into the flow simulation programme that allows to modify the model data during runtime and to implement the remote procedure calls. Feflow meets this requirement as it provides the interface manager (IFM). The mode of operation is explained with a simple test case including an inundation model and a Feflow groundwater model.

Predicting and characterising groundwater flow and solute transport in engineering and hydrogeological applications, such as dimensioning tracer experiments, rely primarily on numerical modelling techniques. During software selection for numerical modelling, the accuracy of the results, financial costs of the simulation software, and computational resources should be considered. This study evaluates numerical modelling approaches and outlines the advantages and disadvantages of several simulators in terms of predictability, temporal control, and computational efficiency conducted in a single user and single computational resource set-up. A set of well-established flow and transport modelling simulators, such as MODFLOW/MT3DMS, FEFLOW, COMSOL Multiphysics, and DuMuX were tested and compared. These numerical simulators are based on three numerical discretisation schemes, i.e., finite difference (FD), finite element (FE), and finite volume (FV). The influence of dispersivity, potentially an artefact of numerical modelling (numerical dispersion), was investigated in parametric studies, and results are compared with analytical solutions. At the same time, relative errors were assessed for a complex field scale example. This comparative study reveals that the FE-based simulators COMSOL and FEFLOW show higher accuracy for a specific range of dispersivities under forced gradient conditions than DuMuX and MODFLOW/MT3DMS. FEFLOW performs better than COMSOL in regard to computational time both in single-core and multi-core computing. Overall computational time is lowest for the FD-based simulator MODFLOW/MT3DMS while the number of mesh elements is low (here < 12,800 elements). However, for finer discretisation, FE software FEFLOW performs faster.

The geometric characteristics of multiple geothermal boreholes organized in a geothermal system affect its thermal efficiency. The location of boreholes and their verticality and straightness is often distorted during drilling process. This distortion then degrades thermal properties of such a system. To study this phenomenon a specialized software tool was developed for numerical modeling based on a simplified mathematical model. This paper describes software tool briefly and presents some initial numerical models of basic borehole arrangements solved by this tool. Paper also contains a verification calculated by specialized software FEFLOW.

Conditions were considered of complex geology and the hydrogeology of Minqin, the 3d numerical simulation model of groundwater system was built by FEFLOW software in the study area. Author found that hydrogeologic parameters which have been debugged many times corresponded with the hydrogeology prospecting results well. Verification results show that the model has better simulation effect and higher reliability in checking the model. Facts show that prediction of groundwater flow field has high reliability in the study area.

The amount of research conducted on geothermal energy as a source for heating and cooling demands of buildings, as well as for electrical energy production, has increased substantially in the past decades. The simulation of freezing and thawing is important for geothermal applications involving ground coupled heat pumps. One area of research is the development of grout cements for borehole heat exchangers (BHE). In many cases, BHEs are operated at temperatures below 0° C due to manifold reasons. Hence, the simulation of freezing and thawing cycles (FTC) is important for such geothermal applications, especially in cold regions. Recently, a testing device for measuring and quantifying the influence of FTC stresses on the mechanical integrity and hydraulic properties of BHE grouts was developed (Anbergen, published in 2014). The testing procedure simulates the downhole in situ conditions as confining radial earth pressure, freezing, and thawing directions from the inside to the outside and under saturated conditions. The hydraulic conductivity can be measured in axial flow direction. Thus, statements regarding the susceptibility of grouts against cyclic freezing and thawing stresses can be made. These results differ substantially from earlier findings, as in situ boundary conditions were not simulated sufficiently. For the verification of the procedure’s thermal process, temperature logs were recorded using thermocouples and thermography imaging. The thermal process was simulated using the finite element method (FEM) groundwater, heat, and mass modeling software FEFLOW. FEFLOW is a common software solution for thermohydraulic coupled groundwater applications with mass transport, as well as geothermal applications. However, up until now, the program could not yet simulate phase changes between solid and liquid phases. To enable the program for such simulations, a plug-in was developed. To do this, a C++ code was written and coupled to the simulation routine of the FEM software. The code is based on a modification of the material parameters of fluid and the incorporation of the latent heat effects in the fluid heat capacity. A linear and an exponential approach for the latent heat release were implemented and benchmarked. The code was verified using different analytical solutions and other FEM codes. Finally, the experimental results of the test procedure could be successfully computed using the new plug-in. Thus, it is now possible to compute phase changes with FEFLOW for geothermal applications as well as other applications like permafrost research.

The model of artificial wetland is designed using the data of hydrology and water quality, to analyze influence of estuary wetland on water environmental capacity in Yangguan-river. The change of concentration of COD and TN is simulated by inputting the model to FEFLOW software. Environmental capacity is calculated on condition that sewage plant is discharging upstream. The result shows that, water quality and environmental capacity are improved by wetland. Environmental capacity of COD can meet the water quality target, but TN cant meet the target because of the high background concentration. This conclusion can be used to formulate or modify the environmental protection and plan.

Groundwater is one of the very sensible natural resource and to protect its quality there is need of proper management system. Groundwater modelling is very advance method for the simulation, forecasting and set remediation strategy to protect the ground-water system, it is an emerging field in groundwater study. So many scientists and researchers are working on this to prepare a groundwater management strategy and to improve the efficiency of the model. For solving the different groundwater related issues, it is important to select proper model. For the accuracy of the model result, it needs to have proper idea about the model, procedure of model run and selection of model basing on the problems. There are a smaller number of modelling software like SWAT, MODFLOW, MT3DMS, RT3D, MT3D, FLUXOS, CXTFIT, FEFLOW, Retraso-Code-Bright etc. Sometimes coupled models are also preferable as per the problem. This paper based on review of the general characteristics of different transport modelling software, methodology of the model development and its application in the different issues related to groundwater development and management.

In order to figure out seepage field in aquifer under the coal seam, the geology and hydrogeology conditions systematically of study area were analyzed, hydrogeological conceptual model was generalized, mathematical model was built, seepage field of the Taiyuan limestone aquifer was simulated with software Feflow. Simulation results show that hydrogeological parameters of Taiyuan limestone aquifer change greatly in different partitions. The model also indicates the heterogeneity of karst fissure of Taiyuan limestone aquifer. The drainage quantity is from the Ordovician limestone aquifer besides supplying from runoff of upstream and capture excretion of downstream. The research is an attempt to simulate the seepage field in aquifer under coal seam, to some extent, it also provides a technical basis for safe coal mining and as a reference for simulation constructions of three-dimensional groundwater flow models in similar coal mines.

L’importanza dell’acqua sia per la vita, sia come componente dell’ecosistema globale sta diventando sempre più evidente. Essa è una risorsa che non solo soddisfa i bisogni fondamentali della popolazione umana, ma è anche vitale per tutti gli ecosistemi globali. Una domanda ricorrente è quella di trovare soluzioni per sopperire alla carenza di acqua che si avverte nei periodi estivi; questo “stato di calamità” va a dimostrare la scarsa conoscenza idrogeologica della risorsa idrica disponibile. Il tutto si traduce in una mancanza di strumenti idonei per affrontare con competenza e con tranquillità anche le situazioni più critiche che si possono presentare. L’obiettivo fondamentale di questo progetto è quello di mostrare come il monitoraggio delle falde sotterranee e l’applicazione della modellazione numerica allo studio degli acquiferi possa fornire un valido supporto scientifico alla progettazione e alle politiche di gestione per il corretto utilizzo e la salvaguardia delle risorse idriche del territorio. Nello specifico, è stato preso come riferimento il territorio del Bacino trasfrontaliero del Fiume Roia concentrando le analisi soprattutto nella parte sud dello stesso, in un’area di circa 1,8 km2, collocata poco a nord dell’abitato di Ventimiglia, dove il Fiume Roia si incontra con il suo maggiore affluente, il Torrente Bevera. L’acquifero presente in quest’area, per quantità e qualità, è uno dei più importanti serbatoi naturali della Liguria. Per quanto riguarda l’utilizzo della risorsa, infatti, le sue acque soddisfano i fabbisogni idrici sia del territorio francese (Mentone, Nizza, Montecarlo, ecc.) sia del territorio italiano (Ventimiglia, Bordighera, Imperia, Sanremo, ecc.), “dissetando” circa 350.000 utenze in Italia e circa 120.000 utenze in Francia. In particolare, questo studio idrogeologico, dopo una preventiva analisi ed un monitoraggio di dati di natura idrologica e idrogeologica (dati pluviometrici, idrometrici, piezometrici, di portata fluviale e di qualità delle acque sotterranee), ha affrontato la ricostruzione geometrico-strutturale del sottosuolo sulla base delle indagini geognostiche a disposizione grazie alle quali è stata evidenziata la presenza di un unico corpo acquifero, a falda libera, di spessore medio di circa 29,8 m, composto in prevalenza da ghiaie sabbiose, talvolta limose, con ciottoli e caratterizzato da un elevato grado di permeabilità (0,8-1 × 10-2m/s), limitato alla base da un substrato a bassa permeabilità costituito dai Flysch di Ventimiglia. E’ stata definita la caratterizzazione idrodinamica dell’acquifero mediante l’utilizzo dei dati raccolti durante una campagna di rilevamento piezometrica su 28 punti di misura nel periodo Luglio 2012 – Luglio 2013. Sulla base di queste conoscenze è stato realizzato il modello concettuale dell’acquifero, base fondamentale della modellazione numerica. Il sistema acquifero è stato quindi rappresentato, per mezzo di un modello numerico tridimensionale ad elementi finiti (FEM), con l’utilizzo del codice numerico FEFLOW (Finite Element subsurface FLOW system), operando in regime permanente e transitorio. I dati di input sono stati inseriti el sistema attraverso l’assegnazione di condizioni ai limiti (Boundary Condition) di carico idraulico, di trasferimento di flussi, di emungimenti e delle proprietà dei materiali (Material Properties) come la permeabilità, la porosità e l’infiltrazione. I risultati finali hanno permesso di stimare i quantitativi d’acqua presenti all’interno della porzione di acquifero in studio mettendo in risalto l’importanza e il ruolo che ricopre il fiume Roia e la quantità d’acqua che esso scambiata con la falda idrica che riesce a bilanciare e a mantenere in equilibrio tutto il sistema anche a fronte dei circa 44 × 106 m3 annui (circa 1,4 m3/s) prelevati dai pozzi presenti. Al fine di mostrare le potenzialità di questa tipologia di studio e ipotizzare possibili scenari di sfruttamento futuro 3 scenari di flusso dove si è ipotizzato un incremento dello sfruttamento della falda a scopo idropotabile. I risultati hanno messo in evidenza le enormi potenzialità di questo acquifero, il quale risulta in grado di sostenere fino ad un incremento del 70% delle attuali portate emunte, purché esse siano ben distribuite e non concentrate in un unico punto. Infine è stata effettuata la modellazione di trasporto dove sono stati analizzati due probabili scenari di inquinamento che hanno messo in evidenza quanto l’acquifero risulti essere suscettibile all’inquinamento idroveicolato da cui deriva, conseguentemente, la necessità di progettare adeguate misure per la sua salvaguardia, anche per l’importanza che esso ricopre come fonte strategica di approvvigionamento idropotabile.