بررسی عددی رفتار رسوب گذاری جریان گل آلود رهاسازی توده در محیط دارای لایه بندی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 مهندسی مکانیک، دانشگاه زنجان، زنجان، ایران

2 گروه مهندسی مکانیک، دانشکده فنی و مهندسی، دانشگاه زنجان

3 دانشجوی کارشناسی ، مهندسی مکانیک، دانشگاه زنجان، زنجان، ایران

چکیده

در این مقاله شبیه‌سازی عددی سه بعدی به منظور مطالعه رفتار رسوب‌گذاری جریان گل آلود رهاسازی توده در محیط دارای لایه بندی چگالی انجام شده است. شبیه‌سازیها به روش شبیه‌سازی گردابه‌های بزرگ انجام شده است. نتایج به دست آمده در حضور لایه بندی تطابق خوبی با نتایج آزمایشگاهی دارند. همچنین حضور لایه بندی چگالی در محیط، باعث کاهش قابل توجه سرعت پیشروی جریان می‌شود، به طوری که مکان پیشانی جریان 57 درصد عقب می‌افتد، ولی تأثیر به-سزایی برروی الگـوی رسـوب‌گذاری ندارد. علاوه بر این، نتایج به دست آمده نشان داد که افزایش شیب تا 12 درجه، باعث افزایش رسوب‌گذاری 15 و 40 درصدی نسبت به شیب‌های 9 و 6 درجه شده است. همچنین، مشاهده شد که افزایش قطر ذرات، باعث کاهش مومنتوم جریان و 75/0 و 7/3 برابر شدن رسوب‌گذاری جریان شده است. با هدف نمایش دقیقتر برهم‌کنش ذرات روی هم، سرعت سقوط ذرات به صورت متغیر با غلظت نیز در نظر گرفته شده است. نتایج این تحلیل نشان می‌دهد که متغیر درنظر گرفتن سرعت سقوط ذرات در مراحل اولیه پیشروی جریان باعث تغییر ناچیزی در سرعت پیشانی می‌شود ولی در ادامه، در نظر گرفتن سرعت سقوط متغیر برای ذرات، سرعت بیشتری را برای پیشانی جریان پیش‌بینی می‌کند. در حالت سرعت متغیر مکان جدایش جریان 22 درصد افزایش می‌یابد.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Numerical Study of Lock Exchange Turbidity Current Depositional Behavior in Stratified Environment

نویسندگان [English]

  • Saba Teymouri 1
  • Ehsan Khavasi 2
  • Hamid Yousefi 3
1 Department of Mechanical Engineering, University Of Zanjan, Zanjan, Iran.
2 Mechanical engineering department, University of Zanjan
3 Department of Mechanical Engineering, University Of Zanjan, Zanjan, Iran.
چکیده [English]

In this paper, three-dimensional numerical simulation was conducted to study the lock exchange turbidity current depositional behavior in a stratified environment. Simulations are carried out using Large Eddy Simulation method. The obtained results in stratified case are in good agreement with experimental data. Also, the presence of stratified environment reduces the current velocity, so that the front location is reduced by 57%, but does not have any significant effect on the sedimentation pattern. In addition, the results showed that increasing the slope to 12 degrees increases the sedimentation rate by 15 and 40 percent compared to the slopes 9 and 6 degrees. It was also observed that increasing the particle diameter reduced the momentum and the current sedimentation increases 0.75 and 3.7 times higher. For more accurate representation of the particle interaction, the particle settling velocity also varies with concentration. The results of this analysis indicate that assuming the variable settling velocity in the early stages of the current progression leads to insignificant change in the front velocity, but when the current propagates more, the faster front velocity will be predicted. In variable velocity case, the current separation location increases by 22%..

کلیدواژه‌ها [English]

  • Density current
  • Lock-exchange
  • Stratified environment
  • Large Eddy Simulation: Sloping bed

مراجع

[1] Z. He, L. Zhao, T. Lin, P. Hu, Y. Iv, H. Ho, Y. Lin, Hydrodynamics of gravity currents down a ramp in linearly stratified environments, Journal Of Hydraulic Engineering, 20(3) (2016) 3-6.
[2] S. Abbaszadeh, Large Eddy Simulation of Continuous Density Current impinging on Obstacles, PhD Thesis, Department of Mechanical Engineering, Sharif University of Technology, Tehran, (2014). (in Persian)
[3] B. L. White, K. R.  Helfrich, A general  description of a gravity current front propagating in a two-layer stratified fluid, Journal of Fluid Mechanics, 711 (2012).
[4] Francisco, P. Ezequiel, L. F.R. Espath, J. H. Silvestrini, Direct numerical simulation of bi disperse particle-laden gravity currents in the channel conFig.uration, Applied Mathematical Modelling, 49 (2017) 739-752.
[5]   MM. Nasr-Azadani, E. Meiburg, Influence of seafloor topography on the depositional behavior of bi-disperse turbidity currents: a three-dimensional, depth- resolved numerical investigation, Environmental Fluid Mechanics, 14(2) (2014a) 319–342.
[6]   MM. Nasr-Azadani, E. Meiburg, Turbidity currents interacting with three-dimensional seafloor topography, Journal of Fluid Mechanics, 745 (2014b) 409–443.
[7]    B. Kneller, W. D. McCaffrey, Depositional effects of flow nonuniformity and stratification within turbidity currents approaching a bounding slope; deflection, reflection, and facies variation, Journal of Sediment Research, 69(5) (1999) 980–991.
[8]   E. Meiburg, B. Kneller, Turbidity currents and their deposits, Annual Reviews of Fluid Mechanics, 42(1) (2010) 135–156.
[9]  S. Migeon, B. Savoye, E. Zanella, T. Mulder, J. C. Fauge`res, O. Weber, Detailed seismic-reflection and sedimentary study of turbidity sediment waves  on the Var Sedimentary Ridge (SE France): significance for sediment transport and deposition and for the mechanisms of sediment-wave construction, Marine Petrolium Geology, 18(2) (2001) 179–208.
[10] T. Nakajima, M.  Satoh,  The  formation  of large mudwaves by turbidity currents on the levees  of the Toyama deep-sea channel, Japan Seasonal Sedimentology, 48(2) (2001) 435–463.
[11] J. P. Syvitski, C. R. Alexander, ME. Field, J. V. Gardner, D. L. Orange, J. W. Yun, Continental-slope sedimentation: the view from northern California, Oceanography, 9(3) (1996) 163–167.
[12] R. B. Wynn, D. A. V. Stow, Classification and characterization of deep-water sediment waves, Marine Geology, 192(1) (2002) 7-22.
[13] IA. Kane, WD. McCaffrey, J. Peakall, BC. Kneller, Submarine channel levee shape and sediment waves from physical experiments, Sedimentary Geology, 223(1) (2010) 75–85.
[14] E. Khavasi, B. Firoozabadi, and H. Afshin, “Linear analysis of the stability of particle-laden stratified shear layers,” Canadian Journal of Physics, 91 (2013) 1–13.
[15] G. V. Middleton, Experiments on density and turbidity currents—I: Motion of the head, Canadian Journal of Earth Science, 3(4) (1996a) 523–546.
[16] G. V. Middleton, Experiments on density and turbidity currents—II: Uniform flow of density currents, Canadian Journal of Earth Science, 3(5) (1966b) 627–637.
[17] M. Nayamatullah, K. Bhaganagar, Turbulent Mixing in 2-D and 3-D Density Currents over a Slope, Journal of Oceanography & Earth Science, 1(1) (2017) 1-11.
[18] P. Beghin, E. J. Hopfinger, R. E. Britter, Gravitational convection from instantaneous sources on inclined boundaries, Journal of Fluid Mechanics, 107 (1981) 407–422.
[19] T. Maxworthy, R. I. Nokes, Experiments on gravity currents propagating down slopes—Part 1: The release of a fixed volume of heavy fluid from an enclosed lock into an open channel, Journal of Fluid Mechanics, 584 (2007) 433–453.
[20] T. Maxworthy, Experiments on gravity currents propagating down slopes—Part 2: The evolution of a fixed volume of fluid released from closed locks into a long, open channel, Journal of Fluid Mechanics, 647 (2010) 27–51.
A. Dai, Experiments on gravity currents propagating on different bottom slopes, Journal of Fluid Mechanics, 731 (2013a) 117–141.
[21] Dai, Non-Boussinesq gravity currents propagating on different bottom slopes, Journal of Fluid Mechanics, 741 (2014) 658–680.
[22] Cortés, F. J. Rueda, M. G. Wells, Experimental observations of  the  splitting  of  a  gravity  current  at a density step in a stratified water body, Journal Geophysical Research in Oceans, 119(2) (2014) 1038–1053.
[23] M. M. Nasr-Azadani, B. Hall, E. Meiburg, Polydisperse turbidity currents propagating over complex topography: comparison of experimental and depth-resolved simulation results, Computer & Geosciences, 53 (2013) 141–153.
[24]  T. Tokyay, M. H. García, Effect of  initial  excess density and discharge on constant flux gravity currents propagating on a slope, Environmental Fluid Mechanics, 14(2) (2014) 409-429.
[25]  L. Ottolenghi, C. Adduce, R. Inghilesi, F. Roman, V. Armenio, Mixing in lock-release gravity currents propagating up a slope, Physics of Fluids, 28(5) (2016) 400-409.
[26]  P. G. Baines, Mixing in flows down gentle slopes into stratified environments, Journal of Fluid Mechanics, 443(2) (2001) 237–270.
[27]  P. Samothrakis, A. J. Cotel, Propagation of a gravity current in a two-layer stratified environment. Journal of Geophysical Research in Oceans, 111 (C1) (2006a) 281–291.
[28]  K. Snow, B. R. Sutherland, Particle-laden flow down a slope in uniform stratification, Journal ofFluid Mechanics, 755 (2014) 251–273.
[29]  M. Nicholson, M. Flynn, Gravity current flow over sinusoidal topography in a two-layer ambient Gravity current  flow  over  sinusoidal  topography  in a two-layer ambient, Department of Mechanical Engineering and Institute for Geophysical Research, University of Alberta, Edmonton, Alberta T6G 2G8 (2015).
[30]  E. Biegert, B. Vowinckel, R. Ouillion, E. Meiburg, High-resolution simulations of turbidity currents, Progress in Earth and Planetary Science, 4(1) (2017) 33-40.
[31]  M. Mahdinia, B. Firoozabadi, M. Farshchi, A.G. Varnamkhasti, H. Afshin, Large Eddy Simulation of Lock-Exchange Flow in a Curved Channel, Journal of Hydraulic Engineering, 138(1) (2011) 57-70.
[32]  P. Moin, J. Kim, Numerical investigation of turbulent channel flow, Journal of Fluid Mechanics, 118 (1982) 341-377.
[33]  S.K. Ooi, G. Constantinescu, L. Weber, Numerical simulations of lock exchange compositional gravity current, Journal of Fluid Mechanics, 635(2009) 361- 388.
[34]  J. Paik, A. Eghbalzadeh, F. Sotiropoulos, Three-Dimensional Unsteady RANS Modeling of Discontinuous Gravity Currents in Rectangular Domains, Journal of Hydraulic Engineering, 135(6) (2009) 505-521.
[35] J. O. Shin, S. B. Dalziel, P. F. Linden, Gravity currents produced by lock exchange, Journal of Fluid Mechanics, 521 (2004) 1-34.
[36] D. Lilly, A proposed modification of the Germano subgrid-scale closure method, Physics of Fluids, 4(3) (1992) 633-635.
[37] Lack, Numerical simulation of containing particle in secondary sediment basins to increase productivity, PhD Thesis, Department of Mechanical Engineering, Sharif University of Technology, Tehran, (2016). (in Persian)
[38]  X. Liu, M. H .García, Computational fluid dynamics modeling for the design of large primary settling tanks, Journal of Hydraulic Engineering, 137(3) (2010) 343-355.
[39] Tamayol, B. Firoozabadi, M. Ashjari, Hydrodynamics of secondary settling tanks and increasing their performance using baffles, Journal of Environmental Engineering, 136(1) (2010) 32-39.
[40] M. Garcia, Hydraulic jumps in sediment-driven bottom currents, Journal of Hydraulic Engineering, 119(10) (1993) 1094–1117.
[41] H. Yousefi, E. Khavasi, S. Teymouri, P. Nazmi, Z. Mashhadi, The Eulerian-Lagrangian and Eulerian- Eulerian methods combination for numerical modeling of the particle laden density current, Modarres Mechanical Engineering, 18(1) (2018) 441-451. (in Persian)
نشریه مهندسی مکانیک امیرکبیر
دوره 51، شماره 6
بهمن و اسفند 1398
صفحه 1235-1252

فایل ها

هم رسانی

ارجاع به این مقاله

آمار