بررسی تأثیر ارتفاع و فاصله موانع متوالی در کنترل جریان غلیظ

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانش آموخته دکتری سازه های آبی دانشگاه لرستان.

2 استاد گروه مهندسی آب دانشکده کشاورزی دانشگاه لرستان

3 استاد گروه سازه های آبی دانشکده مهندسی آب و محیط زیست دانشگاه شهید چمران اهواز.

4 دانشیار گروه مهندسی آب دانشکده کشاورزی دانشگاه لرستان.

چکیده

یکی از مهم­ترین عوامل کاهش عمر مفید سدها، جریان غلیظ است که عامل اصلی حرکت رسوبات در مخازن سدها می باشد. جریان غلیظ پدیده­ای است که به خاطر تغییرات چگالی بین دو سیال به­وجود می­آید. در مقاله حاضر تأثیر ارتفاع و فواصل موانع متوالی در کنترل جریان غلیظ بررسی می­شود. بدین منظور از سه ردیف مانع با چهار ارتفاع و سه فاصله برای موانع و نیز سه شیب و دو غلظت استفاده شده است. جریان غلیظ استفاده شده هم از نوع نمکی بوده و هم از نوع رسوبی. در مجموع 108 آزمایش به همراه 9 آزمایش شاهد انجام شد. با توجه به تحقیقات گذشته حداقل ارتفاع یک مانع برای کنترل کامل جریان غلیظ باید دو برابر ارتفاع جریان غلیظ باشد که در تحقیق حاضر نتایج نشان داد که می­توان با موانعی به ارتفاع یک برابر ارتفاع بدنه جریان غلیظ، تا 99 درصد جریان غلیظ را کنترل کرد. همچنین نتایج نشان داد که در سه ردیف مانع، تأثیر فاصله مانع اول و دوم مهمتر بوده و هرچه این فاصله بیشتر باشد کنترل جریان غلیظ نیز بیشتر است.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigation the effect of the height and distance of successive obstacles on the control of density current

نویسندگان [English]

  • Mohamad Toozandehjani 1
  • Amir Hamzeh Haghiabi 2
  • Mahmood Kashefipour 3
  • Hasan Turabi Podeh 4
1 Phd student of water structures of Lorestan University, Khorramabad, Iran.
2 Professor Faculty of Agriculture, Water Department, University of lorestan, khoram abad, Iran
3 Professor of Department of Water Structurs Faculty of Water and Environmental Engineering, Shahid Chamran University of Ahvaz, Iran.
4 Assistant Professor, Faculty of Agriculture, Water Department, University of lorestan, khoram abad, Iran.
چکیده [English]

Obstacle usually blocks the current and it has been found by other researchers an obstacle with a height more than two times of body height of flow is necessary to fully block the density current. The construction of an obstacle with this elevation creates problems in terms of performance and sustainability as well as the accumulation of sediments behind it.
Rottman et al. (1985) solved the analytical solution of the two-phase current in a horizontal slope with an obstacle in the steady and unsteady flow and concluded that if the height of the obstacle is twice the body height of the density current so the density current is completely blocked. Prinos (1999) conducted studies on the effect of the shape of the obstacle on the current control. In his experiments, he used two semi-circular and triangular obstacles with the same height and concluded that the shape does not have a significant effect on the control of high current. Also, in the range of densimetric Froude number, 0.7 < Frd < 0.8 if the height of the obstacle is twice the height of the body of the density current, the current will be fully restrained. As it has been stated, for a complete block of density current, based on the results of previous investigators, the height of the obstacle should be at least twice the height of the body.
The purpose of this study is to use successive obstacles with lower height, with greater sustainability and lower cost, in controlling density current. For this purpose, in different conditions, in terms of slope and concentration, three rows of obstacles with different heights and also different distances were used to control sedimentary and salty density current.

کلیدواژه‌ها [English]

  • Useful life
  • Dam reservoir
  • slope
  • Sediments
  • Density

مراجع

1- Asghari Pari, S. A., Kashefipour, S.M., Ghomeshi, M. and Shafaie Bajestan, m., 2010. Effects of obstacle heights on controlling turbidity currents with different concentrations and discharges. Journal of Food, Agriculture & Environment, 8 (2), pp. 930 - 935.
 
2- Asghari Pari, S. A., Mohagheghian, S.M., 2014. Numerical analysis the effect of distance variations for uniform and non-uniform successive obstacles and specify priority of them in control of density current. In First National Conference on Challenges on Water resources & Agriculture, Esfahan, Iran. (In Persian).
 
3- Asghari Pari, S. A., Kashefipour, S.M., Ghomeshi, M., 2017. An experimental study to determine the obstacle height required for the control of subcritical and supercritical gravity currents. European Journal of Environmental and Civil Engineering, 21(9), pp. 1080-1092.
 
4- Baines, P. G., 1995.Topographic Effects in Stratified Flows. Cambridge University Press.
 
5- Bursik, M. I. and Woods, A., 2000. The effect of topography on sedimentation from particle-laden turbulent density currents. Journal of Sedimentary Research, 70(1), pp.53-63.
 
6- Greenspan, H.P. and Young, R.E., 1978. Flow over a containment dyke. Journal of Fluid Mechanics, 87(1), pp.179-192.
 
7- Kashefipour, S.M. and Daryaee, M., 2014. Experimental study on control of sedimentary density current by rough bed and obstacle. Journal of Applied Hydrology, 1(2), pp. 11-17.
 
8- Long, R. R., 1954. Some aspects of the flow of stratified fluids. II.Experiments with a two-fluid system. Tellus, pp.97-115.
 
9- Long, R., 1970. Blocking effects in flow over obstacles. Tellus, 22(5), pp.471-480.
 
10- Oehy, C. D., 2003. Effects of obstacles and jets on reservoir sedimentation due to turbidity currents. Communication No.15 of the Laboratory of Hydraulic Structions LCH. Ecole Polytechnique Fédérale de Lausanne EPFL, Switzerland.
 
11- Oehy, C. D. and Schleiss, A.J., 2007. Control of turbidity currents in reservoirs by solid and permeable obstacles. Journal of Hydraulic Engineering, ASCE, 133(6), pp. 637-648.
 
12- Oehy, C. D., Cesar, G. D. and Schleiss, A. J., 2010. Effect of inclined jet screen on turbidity current. Journal of Hydraulic Research, IAHR, 48(1), pp. 81-90.
 
13- Prinos, P., 1999, August. Two-dimensional density currents over obstacles. Proc. In 28 th IAHR Congress CD-ROM (pp. 22-27).
 
14- Rottman, J.W., Simpson, J.E., Hunt, J.C.R. and Britter, R.E., 1985. Unsteady gravity current flows over obstacles: Some observations and analysis related to the phase II trials. Journal of Hazardous Materials, 11, pp.325-340.
 
15- Turner, J. S., 1973. Buoyancy effects in fluids. Cambridge University Press London, U.K., pp. 178-181.
 
16- Zeinivand, M., Kashefipour, S.M. and Ghomeshi, M., 2014. Laboratory Investigation The Effect of Porosity of Permeable Obstacle on Control of Gravity Current. Irrigation Sciences and Engineering, 40(1), pp. 13-24. (In Persian).
علوم و مهندسی آبیاری
دوره 45، شماره 4
اسفند 1401
صفحه 1-14

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سابقه مقاله

  • تاریخ دریافت: 21 مرداد 1399
  • تاریخ بازنگری: 16 آبان 1399
  • تاریخ پذیرش: 20 آبان 1399
  • تاریخ انتشار: 01 اسفند 1401

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