Numerical study of the effect of trapezoidal obstacle in the mixing of muddy flow

Document Type : Research Paper

Authors

• Mohammad Givhighi ¹
• bahareh Pirzadeh ²
• sakineh safari ³

¹ Assistant Professor of Civil Engineering, University of Sistan and Baluchestan, Zahedan,

² Assistant Professor of Civil Engineering Department, Sistan and Baluchestan University, Zahedan

³ Ph.D. student of Water and Hydraulic Structures, Civil Engineering Department, Sistan and Baluchestan University, Zahedan

Abstract

muddy flows are gravitational flows, which are the difference in density or difference in weight of unit volume between two fluids due to suspended sediments. Due to the abundance of these streams in nature knowing and studying the characteristics and factors affective it is imperative and unavoidable. The creation of obstacle in the flow path can affect on the muddy flow character such as flow mixing rate and flow density. In this paper by the Flow 3D software the effect of trapezoidal obstacle in the characteristics of the muddy flow especially its mixing rate has been studied. : In order to Verification, results of the this numerical model Were compared with the results of laboratory work Naji Abhari et al. The results showed that the presence of the obstacle caused the kinetic energy of turbulence to increase by almost 1000% more than Without obstacle. the depth-density variation diagram for two channels showed that the current density in channel With obstacle was less than obstacle-free type. also by increasing 1% the height of obstacle, an average of 2% would be added to the turbulence energy and one-percent increase in the angle of entrance prevented an increase of 1.366 % of the energy of turbulence. Simulation for obstacle with different velocities indicates that with increasing the velocity of the pure water, the amount of maximum energy of turbulence and as a result of flow mixing increases.

Keywords

• muddy flow
• Trapezoidal obstacle
• Flow-3D
• flow mixing
• kinetic energy of turbulence

20.1001.1.20086377.1398.12.43.12.4

---

References

1)       Asgharipri, S. A. And Mohagheghin, S. M. 2015. Numerical Investigation of the Effect of Creating Protective Pits on the Bed on Concentrated Flow Discharge. Journal of Water Resources Engineering. 7 (23): 1-12 (In Persian).

2)    Barahmand, n. And Mousavi, S. R. 2014. Comparison of different turbulence simulations in order to properly simulate dense currents in the vicinity of the bed slope reduction. Journal of Water Resources Engineering, 6 (16): 79-93 (In Persian).

3)    Hosseini, A. And Abdiipour, A. 2011. Application of Flow-3D software in modeling hydrodynamic structure of continuous muddy flow streams entering dams. 9th Iranian Hydraulic Conference. Tarbiat Modares University (In Persian).

4)   Haqqabi, A. H., Abbaspour, B., Maleki, AS. And Torabi Poodeh, h. 2016. Numerical Simulation of Flow Pattern on Triangular Overflows and Comparison with Linear Overflow Using Flow-3D Software. Journal of Water Resources Engineering. 9 (29): 125-137 (In Persian).

5)   Torabi Poudeh, H., Fathi Moghadam, M., M. Ghomeshi and M. Shafai-Bajestan, 2007. Head Velocity and Entrainment of Density Current in an Expansion Reach, Iranian Water Resources Research. Volume 3, No. 1, 56-67 (In Persian).

6)   Tabatabai, S. M., Khazimehnejad, H., Akbarpour, A. And Varjavand, p. 2017. Experimental Investigation of the Effect of Permeable Barrier Arrangement and Bed Slope on Concentrated Hydraulic Characteristics. Dam and Hydroelectric Power Plant. 4 year. No 13 (In Persian).

7)   Sarvinejad, B., Ghomashi, M. And Bina, M. 2013. Investigation of concentration mixing intensity in converged sections and comparison with constant and diverging sections. Irrigation Science and Engineering (Journal of Agricultural Science). Vol. 36. No. 3 (In Persian) .

8)   Salajeghah, A., Ghaini Hesarouieh, M., 2016. Numerical modeling of inlet flow to drinking water tanks. 15th Iranian Hydraulic Conference, Faculty of Engineering, Imam Khomeini International University, Qazvin (In Persian).

9)   Adeli, A., Barani, Gh. And  Zineamat Kermani, M. 2013. Investigation of barrier current condensation control in dams using Fluent software. 5th Iranian Water Resources Management Conference. Shahid Beheshti University (In Persian).

10)  Firoozabad, B. Bagherpour, A. And Afshin, H., 2008. Experimental study of turbulence parameters in brine condensate flow. 11th Fluid Dynamics Conference. Khaje Nasir al-Din Tusi University of Technology, Faculty of Mechanical Engineering (In Persian).

11)  Firoozabad, B. Bagherpour, A. And Afshin, H., 2008. Experimental study of turbulence parameters in brine condensate flow. 11th Fluid Dynamics Conference. Khaje Nasir al-Din Tusi University of Technology, Faculty of Mechanical Engineering (In Persian).

12)  Keshtkar, Sh., Ayubzadeh, SA and Ghodsian, M.Sc. 2017. Experimental study of the effect of barrier height on inhibition of turbulent flow velocity under abrupt change of reservoir bed slope. Journal of Water Resources Engineering. 10 (32): 55-70 (In Persian).

13)   . Marousi, M., Qomashi, M. And Basharvard, h. 2009. Barrier deposition control in dams reservoirs. Eighth International Seminar on River Engineering. Shahid Chamran University. Ahwaz (In Persian).

14)   Mansouri Hafshajani, M., Ghomashi, M. Shafi'i Bejestan, m. 2016. Estimation of mixing intensity in fluid moving around in opposite direction with concentrated flow motion. 6th Iranian National Water Resources Management Conference. The University of Kordestan (In Persian).

15)   Naji Abhari, M., Iranshahi, M., Ghodsian, M. And Firoozabad, b. 2015. Investigation of laboratory observations of the effect of triangular barrier on reservoir floor on muddy stream structure. Journal of Hydraulic. Volume 10. No. 4 (In Persian).

16)   17- Waghefi, M., Akbari, M. And Fayoz, A. 2015. In vitro comparison of three-dimensional flow velocity components around a T-shaped borehole located at 90 degree arc with rigid bed with Flow-3D software results. Journal of Water Resources Engineering. 8 (25): 31-46. (In Persian)

17)   .Anderson, J.D .1995.Computational Fluid Dynamics: The Basics with Applications. New York.

18)   De Cesare, G., D.oehy,C., and J.Schleiss, A. 2008. Experiments on turbidity currents influenced by solid and permeable obstacles and water jet scsreens.

19)   Durbin, P.A. and Pettersson Reif, B.A. 2010. Statistical Theory and Modeling for Turbulent. Norway.

20)   Flow-3D Help. Version 11.1.

21)   Lubbersen, Y.S., Fasaei, F., kroon.P., Boom. R.M. and Schutyser. M.A.I. 2015. Particle suspension concentration with sparse obstacle arrays in a flow channel.Chemical Engineering andProcessing: Process Intensification.

22)   Marosi, M., Ghomeshi, M. and Sarkardeh, H. 2015. Sedimentation control in the reservoirs by using an obstacle. Indian Academy of Sciences.Vol. 40, Part 4.June. pp. 1373–1383.

23)   Varjavand, P., Ghomashi, M.,Hosseinzadeh Dalir, A., Farsadizadeh, B. and Docheshmeh Gorgij, A. 2015. Experimental observation of saline underflows and turbidity currents, flowing over rough beds. Journal Of Civil Engineering. August.

24)   Yaghoubi, S., Afshin, H., Firoozabadi, B. and Farizan, A. 2017. Experimental Investigation of the Effect of Inlet Concentrationon the Behavior of Turbidity Currents in the Presence of TwoConsecutive Obstacles. J. Waterway. Port. Coastal. Ocean Eng.V.143.