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Wyszukujesz frazę "Nawalany, M." wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Scale problems in assessment of hydrogeological parameters of groundwater flow models
Autorzy:
Nawalany, M.
Sinicyn, G.
Powiązania:
https://bibliotekanauki.pl/articles/94506.pdf
Data publikacji:
2015
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
scale problem
upscaling
hydraulic conductivity
hydrogeological models
problem skali
skalowanie
przewodnictwo hydrauliczne
model hydrogeologiczny
Opis:
An overview is presented of scale problems in groundwater flow, with emphasis on upscaling of hydraulic conductivity, being a brief summary of the conventional upscaling approach with some attention paid to recently emerged approaches. The focus is on essential aspects which may be an advantage in comparison to the occasionally extremely extensive summaries presented in the literature. In the present paper the concept of scale is introduced as an indispensable part of system analysis applied to hydrogeology. The concept is illustrated with a simple hydrogeological system for which definitions of four major ingredients of scale are presented: (i) spatial extent and geometry of hydrogeological system, (ii) spatial continuity and granularity of both natural and man-made objects within the system, (iii) duration of the system and (iv) continuity /granularity of natural and man-related variables of groundwater flow system. Scales used in hydrogeology are categorised into five classes: micro-scale – scale of pores, meso-scale – scale of laboratory sample, macro-scale – scale of typical blocks in numerical models of groundwater flow, local-scale – scale of an aquifer/aquitard and regional-scale – scale of series of aquifers and aquitards. Variables, parameters and groundwater flow equations for the three lowest scales, i.e., pore-scale, sample-scale and (numerical) block-scale, are discussed in detail, with the aim to justify physically deterministic procedures of upscaling from finer to coarser scales (stochastic issues of upscaling are not discussed here). Since the procedure of transition from sample-scale to block-scale is physically well based, it is a good candidate for upscaling block-scale models to local-scale models and likewise for upscaling local-scale models to regional-scale models. Also the latest results in downscaling from block-scale to sample scale are briefly referred to.
Źródło:
Geologos; 2015, 21, 3; 179-185
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The velocity oriented approach revisited
Autorzy:
Nawalany, M.
Zijl, W.
Powiązania:
https://bibliotekanauki.pl/articles/2063027.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
velocity oriented approach
continuity of water flux
groundwater flow modeling
Opis:
A great deal of hydrogeological situations requires an extremely accurate calculation of the 3-dimensional groundwater discharge rates in the subsoil. Examples are: hydrology of wetlands, water balances of aquatic ecosystems depending on groundwater recharge, river-groundwater interaction, advective transport of pollution underneath waste disposal sites, particle trajectories in aquifer-aquitard systems with contrasting heterogeneities and many others. Numerical determination of the vertical groundwater velocity is a notoriously difficult problem. In nature this component may be two or three orders of magnitude smaller than the horizontal velocity components. In such cases application of Darcy’s law to the numerically calculated hydraulic heads obtained from a finite difference or finite element model may lead to relatively inaccurate vertical velocities. More specifically, when estimating vertical velocity components in cases where the Dupuit approximation – negligible vertical head gradient – holds, numerical differentiation of hydraulic heads yields zero vertical velocity. In the 1980s of the last century Zijl and Nawalany proposed to invert the order of calculating the velocity field by eliminating the head from Darcy’s law and to consider the Darcy velocity as the primary variable. For 2-dimensional flow this was already common practice and the challenge was a 3-dimensional extension, which was called the Velocity Oriented Approach (VOA). In two dimensions such methods were conventionally based on a stream function as primary variable. However, at that time application of a 3D stream function was not feasible and, therefore, the Darcy velocity itself was considered as the primary variable. This approach has been proven to yield a high accuracy for all three components of the specific discharge, including the relatively small vertical component, especially in cases where the subsoil is smoothly heterogeneous in the horizontal directions. In the 1990s the mixed-hybrid finite element method was developed. The physical interpretation of this method shows the way how to liberate the VOA from its smoothness requirement by introduction of a practical applicable 3D stream function. In conclusion, the velocity oriented approach indicates a change in paradigm regarding the accurate calculation of specific discharge in groundwater flow.
Źródło:
Biuletyn Państwowego Instytutu Geologicznego; 2010, 441 Hydrogeologia z. 10; 113--121
0867-6143
Pojawia się w:
Biuletyn Państwowego Instytutu Geologicznego
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Groundwater and mass transport modelling for documentation and protection of groundwater resources
Autorzy:
Nawalany, M.
Przybyłek, J.
Staśko, S.
Powiązania:
https://bibliotekanauki.pl/articles/2066337.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
przepływ wód podziemnych
transportu masy w wodach podziemnych
ochrona wód podziemnych
pobór wód podziemnych
mathematical modeling
groundwater flow
mass transport in groundwater, groundwater protection
groundwater abstraction
documentation of water resources
Opis:
Short history of mathematical modeling of groundwater flow and transport in Poland is described. It shows brilliant and long tradition of this advanced aspect of hydrogeology. Mathematical modeling has been extensively used in Poland for years in solving practical problems concerning mainly groundwater abstraction, protection of groundwater resources and, recently, as a routine tool for environmental impact assessment whenever groundwater is involved. Use of numerical models in documenting groundwater resources and conditions of their restoration within regional water balance units are recalled. In particular - documenting admissible volumes of groundwater to be abstracted including wells operating in river valleys, determining protection zones for water supply wells and groundwater reservoirs, in particular for major groundwater basins (in Polish: GZWP), investigating optimal ways of abstracting fresh groundwater in areas where mineral waters occur, investigating alternative groundwater sources for supplying large agglomerations. Three examples: defining changes in groundwater chemical composition in conditions of intensive anthropogenic stress on the environment - impact from urban and industrial waste landfills, agriculture, transportation and municipal facilities on groundwater; coexistence of fresh and mineral waters and, finally, quantitative assessments of impacts from open-pit mines on groundwater in the mining stricken area are described in more detail. Last paragraph of the paper is a future looking assessment of aspects of mathematical modeling in Polish hydrogeology that need to be further developed. The aspects concern scientific issues like: scale problem, inverse problems and chemical reactions in subsoil. Also a need of developing specialized software, setting hardware infrastructure and training staff are addressed as the necessary conditions for keeping pace with world's hydrogeology.
Źródło:
Przegląd Geologiczny; 2010, 58, 9/1; 816-823
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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