پیوندهای مفید
اخبار و اعلانات
آمار
| تعداد نشریات | 158 |
| تعداد شماره‌ها | 6,228 |
| تعداد مقالات | 67,747 |
| تعداد مشاهده مقاله | 115,076,087 |
| تعداد دریافت فایل اصل مقاله | 89,810,892 |
تأثیر نفوذپذیری و پخشیدگی مولکولی بر الگوی جریان همرفتی در محیط‌های متخلخل درز و شکاف‌دار | ||
| تحقیقات آب و خاک ایران | ||
| مقاله 20، دوره 46، شماره 2، تیر 1394، صفحه 363-372 اصل مقاله (511.21 K) | ||
| نوع مقاله: مقاله پژوهشی | ||
| شناسه دیجیتال (DOI): 10.22059/ijswr.2015.55940 | ||
| نویسندگان | ||
| مرضیه مالمیر1؛ مجید خلقی2؛ حمیدرضا ناصری3؛ عبدالحسین هورفر2 | ||
| 1دانشجوی دکتری مهندسی منابع آب، دانشکدة مهندسی و فناوری کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران | ||
| 2استاد دانشکدة مهندسی و فناوری کشاورزی، پردیس کشاورزی و منابع طبیعی دانشگاه تهران | ||
| 3دانشیار دانشکدة علوم زمین، دانشگاه شهید بهشتی | ||
| چکیده | ||
| در این مقاله، اثر نفوذپذیری به‌منزلة مشخصه‌ای از محیط متخلخل و پخشیدگی مولکولی به‌منزلة خصوصیتی از املاح بر جریان همرفتی در محیط‌های متخلخل درز و شکاف‌دار، با استفاده از مدل‌سازی‌های عددی مطالعه شده است. مدل مفهومی به‌صورت محیطی متخلخل دارای درز و شکاف‌های منظم عمودی و افقی در نظر گرفته شده است. چهار سناریوی مدل‌سازی با مقادیر متفاوت نفوذپذیری ماتریکس متخلخل و ضریب پخشندگی مولکولی در نظر گرفته شد. نتایج نشان می‌دهد با کاهش ضریب پخشندگی مولکولی، املاح به واسطة حرکت در درز و شکاف‌ها به عمق بیشتری از محیط متخلخل انتقال می‌یابند. همچنین، با افزایش نفوذپذیری ماتریکس متخلخل، سرعت جریان همرفتی افزایش و مقدار املاح بیشتری در محیط متخلخل جریان می‌یابد. | ||
| کلیدواژه‌ها | ||
| جریان و حمل املاح وابسته به چگالی؛ جریان همرفتی؛ محیط متخلخل درز و شکاف‌دار؛ مدل‌سازی عددی | ||
| عنوان مقاله [English] | ||
| Permeability and Molecular Diffusion Effects on Convective Flow Pattern in Fractured Porous Media | ||
| نویسندگان [English] | ||
| Marzieh Malmir1؛ Majid Kholghi2؛ Hamidreza Nassery3؛ Abdolhossein Hoorfar2 | ||
| 1PhD Candidate, Water Resources Engineering, Faculty of Agricultural Engineering and Technology, University College of Agricultural and Natural Resources, University of Tehran | ||
| 2Professor, Faculty of Agricultural Engineering and Technology, University College of Agriculture and Natural Resources, University of Tehran | ||
| 3Associate Professor, Faculty of Earth Sciences, Shahid Beheshti University | ||
| چکیده [English] | ||
| Local differences in fluid density have important role in contaminant transport. Study of variable-density flow and solute transport in fractured porous media is necessary to figure out phenomena like contaminant transport of high density. In this research, the effect of permeability and molecular diffusion, respectively as a characteristic of porous medium and solute, on convective flow in fractured porous media has been studied using numerical modeling by FRAC3DVS/Hydro Geosphere (HGS) model. Conceptual model has been considered as a porous medium contained regular vertical and horizontal fractures. Four scenarios of different porous matrix permeability and free-solution diffusion coefficients have been taken account into the modelling process. The results indicated various patterns of solute transport in fractured porous medium in four different scenarios. So that, in the first one with high molecular diffusion coefficient, the solute is diffused into porous matrix from fractures symmetrically. While in the second scenario, with low molecular diffusion coefficient, the solute is transported in deeper depth and is diffused into porous matrix from fractures in an uprising way, in opposite direction of the contaminant entrance direction. In the next scenario, the more porous matrix permeability, the more convective flow velocity and solute transport in porous matrix. Finally, less differences between the matrix and fracture permeability in the last scenario leads to decrease of the fracture effects on the convective flow pattern, so that flow pattern in the fractured porous medium becomes similar to flow pattern in the homogenous porous medium. | ||
| کلیدواژه‌ها [English] | ||
| fractured porous media, density dependent flow and solute transport, convective flow, Numerical Modeling, FRAC3DVS/HydroGeoSphere (HGS) model | ||
| مراجع | ||
|
Diersch, H. J. G., and O. Kolditz, 2002, Variable-density flow and transport in porous media: Approaches and challenges, Advances in Water Resources 25, 899-944.
Graf, T., 2005, Modeling coupled thermohaline flow and reactive solute transport in discretely-fractured porous media. PhD thesis, Universite´ Laval, Que´bec, Canada, 209 pp.
Graf, T., and R. Therrien, 2005, Variable-density groundwater flow and solute transport in porous media containing nonuniform discrete fractures, Advances in Water Resources 28, 1351-1367.
Graf, T., and R. Therrien, 2007, Coupled thermohaline groundwater flow and single-species reactive solute transport in fractured porous media, Advances in Water Resources 30, 742-771.
Graf, T., and R. Therrien, 2007, Variable-density groundwater flow and solute transport in irregular 2d fracture networks, Advances in Water Resources 30, 455-468.
Graf, T., and R. Therrien, 2008, A method to discretize non-planar fractures for 3d subsurface flow and transport simulations, International Journal for Numerical Methods in Fluids 56, 2069-2090.
Graf, T., and R. Therrien, 2008, A test case for the simulation of three-dimensional variable-density flow and solute transport in discretely-fractured porous media, Advances in Water Resources 31, 1352-1363.
Graf, T., and R. Therrien, 2009, Stable-unstable flow of geothermal fluids in fractured rock, Geofluids 9, 138-152.
Kooi H., J. Groen, and A. Leijnse, 2000, Modes of seawater intrusion during transgressions, Water Resources Research 36, 3581–3589.
Kuznetsov, A. V., and D. A. Nield, 2008, The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium: Double diffusive case, Transport in Porous Media 72, 157-170.
Kuznetsov, A. V., D. A. Nield, and C. T. Simmons, 2010, The effect of strong heterogeneity on the onset of convection in a porous medium: Periodic and localized variation, Transport in Porous Media 81, 123-139.
Nield, D. A., and A. V. Kumetsov, 2007, The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium, International Journal of Heat and Mass Transfer 50, 1909-1915.
Nield, D. A., and A. V. Kuznetsov, 2007, The effect of combined vertical and horizontal heterogeneity on the onset of convection in a bidisperse porous medium, International Journal of Heat and Mass Transfer 50, 3329-3339.
Nield, D. A., and A. V. Kuznetsov, 2007, The effects of combined horizontal and vertical heterogeneity and anisotropy on the onset of convection in a porous medium, International Journal of Thermal Sciences 46, 1211-1218.
Nield, D. A., and A. V. Kuznetsov, 2007, The onset of convection in a shallow box occupied by a heterogeneous porous medium with constant flux boundaries, Transport in Porous Media 67, 441-451.
Nield, D. A., and A. V. Kuznetsov, 2008, The effects of combined horizontal and vertical heterogeneity on the onset of convection in a porous medium: Moderate heterogeneity, International Journal of Heat and Mass Transfer 51, 2361-2367.
Nield, D. A., A. V. Kuznetsov, and C. T. Simmons, 2009, The effect of strong heterogeneity on the onset of convection in a porous medium, Transport in Porous Media 77, 169-186.
Nield, D. A., A. V. Kuznetsov, and C. T. Simmons, 2010, The effect of strong heterogeneity on the onset of convection in a porous medium: 2d/3d localization and spatially correlated random permeability fields, Transport in Porous Media 83, 465-477.
Nield, D. A., and C. T. Simmons, 2007, A discussion on the effect of heterogeneity on the onset of convection in a porous medium, Transport in Porous Media 68, 413-421.
Post, V. E. A., and C. T. Simmons, 2010, Free convective controls on sequestration of salts into low-permeability strata: Insights from sand tank laboratory experiments and numerical modelling, Hydrogeology Journal 18, 39-54.
Prasad, A., and C. T. Simmons, 2003, Unstable density-driven flow in heterogeneous porous media: A stochastic study of the elder 1967b "Short heater'' problem, Water Resources Research 39.
Rayleigh, L., 1916, On convection currents in a horizontal layer of fluid when the higher temperature is on the underside. Philos. Mag., Ser. 6 32, 529–546ŽJ.W. Strutt.
Schincariol, R. A., and F. W. Schwartz, 1990, An experimental investigation of variable density flow and mixing in homogeneous and heterogeneous media, Water Resources Research 26, 2317-2329.
Schincariol, R. A., F. W. Schwartz, and C. A. Mendoza, 1997, Instabilities in variable density flows: Stability and sensitivity analyses for homogeneous and heterogeneous media, Water Resources Research 33, 31-41.
Schincariol RA., 1998, Dispersive mixing dynamics of dense miscible plumes: natural perturbation initiation by local-scale heterogeneities. Journal of Contaminant Hydrology. 34:247–71.
Shikaze, S. G., E. A. Sudicky, and F. W. Schwartz, 1998, Density-dependent solute transport in discretely-fractured geologic media: Is prediction possible?, Journal of Contaminant Hydrology 34, 273-291.
Simmons, C. T., T. R. Fenstemaker, and J. M. Sharp, 2001, Variable-density groundwater flow and solute transport in heterogeneous porous media: Approaches, resolutions and future challenges, Journal of Contaminant Hydrology 52, 245-275.
Simmons, C. T., J. M. Sharp, and D. A. Nield, 2008, Modes of free convection in fractured low-permeability media, Water Resources Research 44.
Therrien R, RG. McLaren, E. A. Sudicky, and SM. Panday, 2009, HYDROGEOSPHERE – A three-dimensional numerical model describing fully-integrated subsurface and surface flow and solute transport. Universite´ Laval, University of Waterloo, 275 pp.
Vujevic, K., T. Graf, C. T. simmons, and A. werner, 2014, Impact of fracture network geometry on free convective flow patterns, advances in water resources 71, 65-80. | ||
|
آمار تعداد مشاهده مقاله: 1,735 تعداد دریافت فایل اصل مقاله: 1,306 |
||