불균질도가 높은 대수층내에서의 비에르고딕 용질이동에 관한 수치 시뮬레이션

Numerical Simulajtions of Non-ergodic Solute Transport in Strongly Heterogeneous Aquiferss

  • 서병민 (충남대학교 기초과학 연구소)
  • Seo Byong-Min (Research Institute of Basic Sciences, Chungnam National University)
  • 발행 : 2005.09.01

초록

균일한 지하수 유속을 가진 불균질한 등방성 대수층 내에서 정류상태로 흐르는 지하수의 흐름과 함께 이동해가는 비반응성 오염물질에 대한 삼차원 몬테카를로 시뮬레이션이 시행되었다. 로그-정규적으로 분포되어 있는 수리 전도도 K(x)가 임의 장으로 설정되었으며 시뮬레이션 동안에 발생 할 수 있는 불확실성을 감소하기 위해 여러 가지 방법들이 시도되었다. 3,200개 오염 운들에 대한 이차공간적률의 집합적평균 $$lt;S_{ij}'(t',l')$gt;$, 그리고 오염 운중심분산 $$lt;R_{ij}'(t',l')$gt;$이 각기 다른세가지 불균질도 $\omega^2_y1.0,$ 2.5 및 5.0에 대해서 시뮬레이션 되었으며 또한 각기 다른 크기의 평균속도에 수직방향인 선형초기오염원( l=1.5 및 10)에 대해서 입자추적이 행하여 졌다 시뮬레이션된 무차원 종적률들은 일차 근사법에 의한 비에르고딕 이론적 결과와 비교적 잘 일치 하나 시뮬레이션된 무차원 횡적률들은 일차근사법에 의한 이론적 결과들과 잘 일치하지 않으며 특히 불균질도가 큰 대수층에 대해서 그리고 초기 선형오염운의 크기가 작은 무차원 횡이차공간적률에 대해서 뚜렷하게 저평가 했다. 시뮬레이션된 집합적 평균이차적률은 에르고딕 상태에 도달하지 못했으며 일차근사법에 의한 에르고딕 용질 이동에 관한 횡이차공간적률은 시뮬레이션 결과를 저평가 했음을 보인다.

Three dimensional Monte-Carlo simulations of non-ergodic transport of a non-reactive solute plume by steady-state groundwater flow under a uniform mean velocity in isotropic heterogeneous aquifers were conducted. The log-normally distributed hydraulic conductivity, K(x), is modeled as a random field. Significant efforts are made to reduce the simulation uncertainties. Ensemble averages of the second spatial moments of the plume, $$lt;S_{ij}'(t',l')$gt;$ and plume centroid variances, $$lt;R_{ij}'(t',l')$gt;$ were simulated with 3200 Monte Carlo runs for three variances of log K, $\omega^2_y1.0,,2.5,$ and 5.0, and three dimensionless lengths of line plume sources ( l=,5 and 10) normal to the mean velocity. The simulated second spatial moment and the plume centroid variance in longitudinal direction fit well to the first order theoretical results while the simulated transverse moments are not fit well with the first order results. The first order theoretical results definitely underestimated the simulated transverse second spatial moments for the aquifers of large u: and small initial plume sources. The ergodic condition for the second spatial moments is far from reaching, and the first order theoretical results of the transverse second spatial moment of the ergodic plume slightly underestimated the simulated moments.

키워드

참고문헌

  1. Ababou, R, Mclaughlin, D., Celhar, L.w. and Tompson, A.F.B., 1989, Numerical simulation of three-dimensional saturated flow in randomly heterogeneous porous media, Transp. Porous Media, 4,549-565
  2. Attinger, S., Dentz, M. and Kinzelbach, W., 2002, Exact Transversal Macro Dispersion coefficients for transport in heterogeneous porous media, ACTA Universitatis Carolinae-Geologica, 46, 2/3, 117-119
  3. Bellin, A, Salandin, P. and Rinaldo, A, 1992, Simulation of dispersion in heterogeneous porous formations: statistics, first order theories, convergence of computations, Water Resour. Res., 28, 9, 2211-2227 https://doi.org/10.1029/92WR00578
  4. Barry, D., Coves, AJ. and Sposito, G, 1988, On the dagan model of solute transport in ground-water application to the Borden site. Water Resour. Res., 24,10,1805-1817 https://doi.org/10.1029/WR024i010p01805
  5. Burr, D.T., Sudicky, E.A. and Naff, R.L., 1994, Nonreactive and reactive solute transport in three-dimensional heterogeneous porous media: Mean displacement, plume spreading, and uncertainty, Water Resour. Res., 30, 3, 791-815 https://doi.org/10.1029/93WR02946
  6. Chin, D.A. and Wang, T., 1992, An investigation of the validity of first order stochastic dispersion theories in isotropic porous media, Water Resour. Res., 28, 6, 1531-1542 https://doi.org/10.1029/92WR00666
  7. Cushman, J.H., 1990, Dynamics of Fluids in Hierarchical Porous Media, Academic. San Diego, Calif
  8. Cushman, J.H., Hu, B.X. and Ginn, T.R, 1994, Nonequilibrium statistical mechanics of preasymptotic dispersion, J. Stat. Phys., 75, 859-878 https://doi.org/10.1007/BF02186747
  9. Cvetkovic, V., Cheng, H. and Wen, X.H., 1996, Analysis of non-linear effects on tracer migration in heterogeneous aquifers using Lagrangian travel time statistics, Water Resour. Res., 32, 6, 1671-1680 https://doi.org/10.1029/96WR00278
  10. Dagan, G, 1988, Time-dependent macrodispersion for solute transport in anisotropic heterogeneous aquifers, Water Resour. Res., 24, 9, 1491-1500 https://doi.org/10.1029/WR024i009p01491
  11. Dagan, G., 1989, Flow and Transport in Porous Formations, Springer-Verlag, Berlin Heidelberg, Germany
  12. Dagan, G., 1990, Transport in heterogeneous porous formations: Spatial moments, ergodicity, and effective dispersion, Water Resour. Res., 26, 6, 1281-1290 https://doi.org/10.1029/WR026i006p01281
  13. Dagan, G, 1991, Dispersion of a passive solute in non-ergodic transport by steady velocity fields in heterogeneous formations, J. Fluid Mech., 233, 197-210 https://doi.org/10.1017/S0022112091000459
  14. Dagan, G. 1995, Comment on 'Nonreactive and reactive solute transport in three-dimensional heterogeneous porous media: Mean displacement, plume spreading, and uncertainty' by T.D. Burr, E.A. Sudicky, and R.L. Naff., Water Resour. Res., 31,5,1439-1441 https://doi.org/10.1029/95WR00090
  15. Dentz, M., Kinzel bach, H., Attinger, S. and Kinzelbach, W., 2002, Temporal behavior of a solute cloud in a heterogeneous porous medium, 3. Numerical simulations, Water Resour. Res., 38, 23-1-13
  16. Federico, V.D. and Zhang. Y.K., 1999, Solute transport in heterogeneous porous media with long-range correlations, Water Resour. Res., 35, 10, 3185-3192 https://doi.org/10.1029/1999WR900021
  17. Garabedian, S.P., Leblanc, D.R., Gelhar, L.W. and Celia, M.A., 1991, Large-scale natural gradient trac¬er test in sand and gravel, Cape Code, Massachusetts. 2. Analysis of Spatial moments for a non-reactive tracer, Water Resour. Res., 27, 5, 911-924 https://doi.org/10.1029/91WR00242
  18. Gelhar, L.W., 1993, Stochastic Subsurface Hydrology, Prentice-Hall. EnglewoodCliffs, New Jersery
  19. Hassan, A., Cushman, J.H. and Delleur, J.W., 1998, A Monte Carlo assessment of eulerian flow and transport perturbation models, Water Resour. Res., 34,1143-1163 https://doi.org/10.1029/98WR00011
  20. Hassan, A., Andricevic, R. and Cvetkovic, V., 2002, Evaluation of analytical solute discharge moments using numerical modeling in absolute and relative dispersion frameworks, Water Resour. Res., 38, 1-1-8
  21. Hill, M.C., 1990, Preconditioned Conjugate Gradient 2 (PCG2), A computer program for solving ground-water flow equations, U.S.G.S. Water Resources Investigations Report, 90,4048
  22. Hubbard,S., Chen, J., Peterson, J., Majer, E.L., Willianms, K.H., Swift, D.J., Mailloux, B. and Rubin, Y., 2001, Hydrogeological characterization of the South Oyster vacterial transport site suing geophysical data, Water Resour. Res., 37, 10, 2431-2456 https://doi.org/10.1029/2001WR000279
  23. Killey, R.W.D. and Moltyaner, G.L., 1988, Twin lake tracer tests: setting methodology, and hydraulic conductivity distribution, Water Resour. Res., 24, 10,1585-1612 https://doi.org/10.1029/WR024i010p01585
  24. Kitanidis, P.K., 1988, Prediction by the method of moments of transport in a heterogeneous formation, Jour. Hydrology, 102, 1-4,453-473
  25. Mackay, D.M., Freyberg, D.L., Roberts, P.V. and Cherry, J.A., 1986, A natural gradient experiment in a sand aquifer, 1. Approach and overview of plume movement, Water Resour. Res., 22, 2017-2030 https://doi.org/10.1029/WR022i013p02017
  26. Pollock, D.W., 1994, User's guide for MODPATH/MODPATH-PLOT, Version 3: A particle tracking post-processing package for MODFLOW, The U.S. Geological Survey finite-difference ground-water flow model, U.S. Geological Survey, Open-File Report, 94-464
  27. Quinodoz, H.A.M. and Valocchi, J., 1990, Macrodispersion m heterogeneous aquifers: Numerical experiments. In: Moltyaner, G. (ed.) International conference and workshop on transport and mass exchange processes in sand and gravel aquifers: field and modeling studies, AGU, Ottawa, Ont., Canada
  28. Rajaram, H. and Gelhar, L.W., 1993, Plume scale-dependent dispersion in heterogeneous aquifer, 1. Lagrangian analysis in a stratified aquifer, Water Resour. Res., 29, 9, 3249-3260 https://doi.org/10.1029/93WR01069
  29. Robin, M.J.L., Cutjahr, A.L., Sudicky, E.A. and Wilson, J.L., 1993, Cross-correlated random field generator with direct Fourier transform method, Water Resour. Res., 29, 7,2385-2397 https://doi.org/10.1029/93WR00386
  30. Rubin, Y., 1990, Stochastic modeling of macrodispersion in heterogeneous porous media, Water Resour. Res., 26, 1, 133-141 https://doi.org/10.1029/WR026i001p00133
  31. Salandin, P., Rinaldo, A. and Dagan, G., 1991, A note on transport in stratified formations by flow tilted with respect to the bedding, Water Resour. Res., 27,11,3009-3017 https://doi.org/10.1029/91WR01937
  32. Salandin, P. and Fiorotto, V., 1993, Numerical simulations of non-ergodic transport in natural formations, Proc. XXV IAHR, Tokyo, 55-62
  33. Selroos, J.O. and Cvetkovic, V., 1994, Mass flux statistics of kinetically sorbing solute in heteroge neous aquifer: Analytical solution and comparison with simulation, Water Resour. Res., 30, 1, 63-69 https://doi.org/10.1029/93WR02654
  34. Selroos, J.O., 1995, Temporal moments for non-ergodic solute transport in heterogeneous aquifers, Water Resour. Res., 31, 7, 1705-1712 https://doi.org/10.1029/95WR00945
  35. Sudicky, E.A. and Naff, R.L., 1995, Reply, Water Resour. Res., 31,5, 1443-1444 https://doi.org/10.1029/95WR00091
  36. Tompson, A.F.B. and Gelhar, L.W., 1990, Numerical simulation of solute transport in three-dimensional, randomly heterogeneous porous media, Water Resour. Res., 25, 10, 2541-2562
  37. Zhang, D. and Neuman, S.P., 1995, Eulerian-Lagrangian analysis of transport conditioned on hydraulic data, 3. Spatial moments, travel time distribution, mass flow rate, and cumu¬lative release across a compliance surface, Water Resour. Res., 31, 1, 65-75 https://doi.org/10.1029/94WR02236
  38. Zhang, Y.K., Zhang, D. and Lin, J., 1996, Non-ergodic solute transport in three-dimensional heterogeneous isotropic aquifers, Water Resour. Res., 32,9, 2955-2963 https://doi.org/10.1029/96WR01467
  39. Zhang, Y.K., and Zhang, D., 1997, Time-dependent dispersion of non-ergodic plumes in two-dimensional heterogeneous porous media, Journal of Hydrologic Engineering, 2, 2, 91-94 https://doi.org/10.1061/(ASCE)1084-0699(1997)2:2(91)
  40. Zhang, Y.K., and Federico, V.D., 1998, Solute transport in three-dimensional heterogeneous media with a Gaussian covariance of log hydraulic conductivity, Water Resour. Res., 34, 8, 1929-1934 https://doi.org/10.1029/98WR01142
  41. Zhang, Y.K. and Lin, J., 1998, Numerical simulations of transport of non-ergodic plumes in heteroge¬neous aquifers, Stochastic Hydrology and Hydraulics, 12, 2, 117-140 https://doi.org/10.1007/s004770050013
  42. Zhang, Y.K. and Federico, D.V., 2000, Nonergodic solute transport in heterogeneous porous me dia: Influence of multiscale structure, in Zhang, D., and Winter, C.L., eds., Theory, Modeling, and Field Investigation in Hydrogology:
  43. A Special Volume in Honor of Shlomo P. Neuman's 60th Birthday: Boulder, Co lorado, Geological Sociery of America Special Paper, 348,61-72
  44. Zhang, Y.K. and Seo, B., 2004, Numerical simulations of non-ergodic solute transport in three-dimen-sional heterogeneous porous media, Stochastic Environmental Research and Risk Assessm ent, 18, 205-215 https://doi.org/10.1007/s00477-004-0178-4