Figure 1 - General diagram of the forehead and body of the concentrated

저수지의 동적 염분 흐름의 실험 및 수치해석적 연구

Authors

1 Water resource expert Khuzestan Water and Power Authority
2 shahid chamran univercity of ahwaz

Since the characteristics of density current is affected by different parameters, the effect of discharge rate changes, gradient and the concentration of density current on speed of the forehead  and also the speed distribution in density current’s body have been investigated by physical and three-dimensional mathematical model (Flow-3d) in this research. For these purposes, different tests in the form of salty density current were done with three inflow discharge rates (0.7, 1 and 1.3 liters per second) and three different slopes (0, 1 and 2.2 percent). As well as to evaluate the effect of density changes on the flow characteristics, the concentration of 10, 15 and 20 grams per liter were used. In order to measure the speed of the forehead, velocity distribution in the body and its changes with flow, density and different slopes, video camera and ultrasound profiler speedometer were used in this study. Then, forehead speed and velocity distribution in the current’s body were achieved using six different turbulence models which are available on the software of “Flow-3D”. Comparing the results of physical and mathematical model showed that Eddy turbulence model and laminar flow mode have better accuracy in relation to other turbulent models. It should be noted that Reynolds number on experiments are at the range of  2000-4000.

밀도 흐름의 특성은 서로 다른 파라미터에 의해 영향을 받기 때문에 방출 속도 변화, 구배 및 밀도 흐름의 농도가 수두 속도에 미치는 영향과 밀도 흐름의 볼륨 속도 분포도 물리적 및 3차원 수학 모델(Flow-3d)에 의해 조사되었습니다.

이러한 목적을 위해 세 가지 유입 배출 속도(초당 0.7, 1 및 1.3L)와 세 가지 다른 경사도(0, 1, 2.2%)로 염분 밀도 흐름 형태의 다른 테스트가 수행되었습니다.

밀도 변화가 흐름 특성에 미치는 영향을 평가하기 위해 리터당 10, 15, 20g의 농도를 사용했습니다. 이 연구에서는 수두의 속도를 측정하기 위해 체내의 속도 분포와 흐름, 밀도 및 다양한 기울기와 함께 변화된 속도, 비디오 카메라 및 초음파 프로파일러 속도계를 사용했습니다.

그런 다음, “Flow-3D” 소프트웨어에서 사용할 수 있는 6가지 난류 모델을 사용하여 현재 볼륨의 수두 속도와 속도 분포를 달성했습니다.

물리적 모델과 수학적 모델의 결과를 비교한 결과, 에디 난류 모델과 층류 모드가 다른 난류 모델과 비교하여 더 나은 정확도를 가지고 있다는 것을 보여주었습니다.

레이놀즈 실험 번호는 2000-4000 범위라는 점에 유의해야 합니다.

Figure 1 - General diagram of the forehead and body of the concentrated
Figure 1 – General diagram of the forehead and body of the concentrated
Figure 2 - Dimensional profile of velocity distribution in concentrated flow (Graph and Altinacar, 1662)
Figure 2 – Dimensional profile of velocity distribution in concentrated flow (Graph and Altinacar, 1662)
Figure 1 - Schematic drawing of the physical model used
Figure 1 – Schematic drawing of the physical model used
Figure 0 - Sample of the concentrated flow created in the laboratory (front and body of concentrated flow)
Figure 0 – Sample of the concentrated flow created in the laboratory (front and body of concentrated flow)
Figure 6 - Mixing intensity values against Richardson number and comparing it with the results of other researchers
Figure 6 – Mixing intensity values against Richardson number and comparing it with the results of other researchers

Reference

1- حقی آبی، ا. 1383. بررسی اثر شیب کف بر پروفیل سرعت جریان غلیظ رساله دکتری رشته سازه های آبی ، دانشکده مهندسی علوم آب، دانشگاه شهید چمران اهواز.

2- کاهه، م. قمشی، م. و س، ح، موسوی جهرمی، 1391. بررسی آزمایشگاهی سرعت پیشروی جریان غلیظ بر روی سطوح زبر. علوم و مهندسی آبیاری، 35(1): 101-110.

3- کشتکار، ش. ایوب زاده، س ع. و ب، فیروزآبادی، 1389 . بررسی پروفیل سرعت و غلظت جریان گل آلود با استفاده از مدل فیزیکی. پژوهش‌های آبخیزداری،87(2): 43-36.

4- کوتی، ف. کاشفی پور، س، م. و م قمشی، 1391. تجزیه و تحلیل پروفیل های سرعت در جریان غلیظ. مجله ی علوم و فنون کشاورزی و منابع طبیعی، علوم آب و خاک، 59: 29-15.

5- Altinakar, M.S., Graf, W.H. and , E.J, Hopfinger. 1990. Weakly depositing turbidity current on a small slope. Journal of Hydraulic Research. 28(1): 55-80.

6- Baas, J.H. McCaffrey, W.D. Haughton P.D.W. and C, Choux. 2005. Coupling between suspended sediment distribution and turbulence structure in a laboratory turbidity current. Journal of Geophysics Research, 110: 20-32.

7- Barahmand, N. and A, Shamsai. 2010. Experimental and theoretical study of density jumps on smooth and rough beds”. Lakes and Reservoirs: Research and Management, 15(4): 285-307.

8- Britter, R.E. and P, Linden. 1980.The motion of the front of a gravity current traveling down an incline. Journal of Fluid Mechanics, 99(3): 531- 543.

9- Buckee, C. Kneller, B. and J, Peakall. 2001. Turbulence structure in steady solute-driven gravity currents Blackwell Oxford pp, 173-188.

10- Choux, C.M.A. Baas, J.H. McCaffrey, W.D. and P.D.W, Haughton. 2005. Comparison of spatio–temporal evolution of experimental particulate gravity flows at two different initial concentrations based on velocity grain size and density data. Sedimentary Geology, 179: 49-69.

11- FathiMoghadam, M. TorabiPoudeh, H. Ghomshi, M. and M, Shafaei. 2008. The density current head velocity in expansion reaches. Lakes & Reservoirs: Research & Management, 13(1): 63-68.

12- Ghomeshi, M. 1995. Reservoir sedimentationmodeling. Ph.D. Thesis. University of Wollongong. Australia.

  1. Graf, W.H. and M, S, Altinakar. 1998. Fluvial Hydraulics, Flow and Transport Processes in Channels of Simple Geometry. John Wiley and Sons, Ltd, England.

14- Ieong, K, K. Mok, K,M. and H, Yeh. 2006. Fluctuation of the front propagation speed of developed gravity current. Journal of Hydrodynamics, 18(3): 351-355.

15- LaRocca, M. Adduce, C. Sciortino, G. And A, B, Pinzon. 2008. Experimental and numerical simulation of three-dimensional gravity currents on smooth and rough bottom. Physics of Fluids, 20, 106603.

16- McCaffrey, W, D. Choux, C, M. Baas, J, H. And P, D, W, Haughton. 2003. Spatio-temporal evolution of velocity structure concentration and grainsize stratification within experimental particulate gravity currents. Marine and Petroleum Geology. 20: 851-860.

17- Sequeiros, O, E. Spinewine, B. Beaubouef, R, T. Sun, T. Garcia, H. M., and G, Parker. 2010. Characteristics of Velocity and Excess Density Profiles of Saline Underflows and Turbidity Currents Flowing over a Mobile Bed”. Journal of Hydraulic Engineering, 136(7): 167-180.

18- Turner, J, S. 1973. Buoyancy Effects in Fluids. Cambridge University Press London, U.K, pp. 178-181.

19- Yu, W, S. Lee, H, Y. And M, S, Hsu. 2000. Experiments on deposition behavior of fine in a reservoir. Journal of Hydraulic Engineering, 126(12): 912-920.