Document Type : Original Manuscript

Authors

Assistant Professor, Department of Engineering, Behbehan Khatam Alanbia University of Technology

Abstract

Turbidity currents are one of the most fundamental factors that transferring sediment near the dam. In this article, the effect of roughness, pattern, height and the shape of roughness in the floor on controlling turbidity current are studied using finite elements numerical method by ANSYS-CFX. For solving turbulence equations are used K-e method. After calibrating of model has done, at the first, simulated flow without roughness and then three shape of roughness pyramid-shaped, round edge cylindrical and cubic with two alternative zigzag and consecutive, with 5 different height and for subcritical and supercritical flow regime are modeled. The results indicated that with the increase in height of the roughness and cross flow and with zigzag arrangement, reduced the turbidity current discharge. Also the effect of roughness on controlling subcritical turbidity current are more than supercritical flow.

Keywords

Main Subjects

Asghari Pari, S. A. 2010.Investigation the effect of obstacle’s height on reservoir sedimentation by turbidity current, PhD thesis, Faculty of Water Science Engineering, Shahid Chamran University, Ahwaz, Iran.
Asghari Pari, S. A., Kashefipour, S. M., Ghomshi, M. and Shafaie Bajestan, M. 2010.  Investigation the effect of concentration on controlling turbidity current by obstacle in dam reservoirs, 8th International River Engineering Conference, Shahid Chamran University Ahwaz, Iran.
Bahrami, H., Ghomshi, M. and Kashefipour, S. M. 2010. Experimental study of the bed slope failure on the flow properties of gravity current. J. Mar. Sci. Technol.8 (3):67-76
Poorkayed, S., Hasoonizade, H., Nekoeyanfar, Kashefipour, S. M., and Daryaee, M. 2013. Investigate the effects of slope and roughness on the forehead speed density current deposits using physical models, 8th International River Engineering Conference, Shahid Chamran University Ahwaz, Iran.
Daryaee, M., Kashefipour, S. M. Ghomshi, M. 2015.Study of obstacle and roughness impacts on controlling sedimentary density current, Water Soil Sci., 24(4): 1-9.
Gorban Moghadam, A. A., Ghomshi, M. and Nasrollahpour, R. 2013. Experimental investigation of effect cylindrical barriers on Characteristics of Density Currents Head. 8th International River Engineering Conference, Shahid Chamran University Ahwaz, Iran.
Kaheh, M., Ghomshi, M., and Musavi Jahromi, S., H. 2011. Experimental Investigation of density current forward speed on rough surfaces, J. Irrig. Sci. Eng. 35(1):101-109.
Vargavand, P., Hosseinzadeh Dalir, A., Ghomeshi, M. and Farsadizadeh, D. 2013. Experimental Study on the Effects of Artificial Bed Roughness on Instantaneous Velocity Fluctuations of Saline Density Currents. J. Water Soil.27 (4):839-849.
Bursik, M., I. and Woods, A. 2000.The effect of topography on sedimentation from particle-laden turbulent density currents. J. Sedimentary Res. 70(1): 53-63.
Ellison, T., H. and Turner, J., S. 1959.Turbulent entrainment in stratified flow. J. Fluid Mech. 6(3): 423 – 448.
Kubo, Y. 2004. Experimental and numerical study of topographic effects on deposition from tow-dimensional, particle-driven density currents, J. Sedimentary Geo., 164(3):311-326.
Nasr-Azadani, M., M. Meiburg, E. 2011. TURBINS: An immersed boundary, Navier–Stokes code for the simulation of gravity and turbidity currents interacting with complex topographies. Comput. Fluids. 45(1): 14–28.
Nogueira, H.I.S., Adduce, C., Alves, E., And Franca, M.J. 2013. Analysis of lock-exchange gravity currents over smooth and rough beds. J.  Hydraul. Res., 51(4):417–431.
Oehy, CD, and Schleiss, Anton. 2001. Numerical modelling of a turbidity current passing over an obstacle–Practical application in the Lake Grimsel, Switzerland. Paper presented at the Proceedings of the 2001 Congress _CD-ROM_, Graz, Austria, Theme D.
Oehy, Ch. 2002. Effects of obstacles and jets on reservoir sedimentation due to turbidity currents. Communication 15 of the Laboratory of Hydraulic structions _LCH_, Ecole Polytechnique Fédérale de Lausanne _EPFL_, Switzerland.
Oehy, Ch. and Schleiss, A. 2007. Control of turbidity currents in reservoirs by solid and permeable obstacles. J. Hydraul. Eng. 133 (6):637 –648.
Nasrollahpour, R. and Ghomeshi, M. 2012. Effect of roughness geometry on characteristics of density currents head. Indian J.  Sci. Technol. 5(12): 3783-3787.
Migeon, S. Mulder, T. Savoye, B. and Sage, F. 2012. Hydrodynamic processes, velocity structure and stratification in natural turbidity currents: Results inferred from field data in the Var Turbidite System. J. Sedimentary Geo. 245–246(0): 48–62.
Sequeiros, O., Spinewine, B., Beaubouef, R., Sun, T., García, M., & Parker, G. 2010. Characteristics of velocity and excess density profiles of saline underflows and turbidity currents flowing over a mobile bed. J. Hydraul. Eng., 136(7): 412-433