Journal of Computational & Applied Research in Mechanical Engineering (JCARME)

Document Type : Research Paper

Author

Mahdi Moghimi

Iran university of science and technology Mechanical Engineering Department

https://doi.org/10.22061/jcarme.2018.1627.1140

Abstract

Using experimental models along with conducting numerical analysis have been widely used in performance recognition and optimization of hydraulic equipments. Numerical modeling has lower cost rather than experimental one; however practical tests are commonly used because of the hydraulic structure importance especially in dams. Meanwhile numerical methods could be used for future designs through validating numerical models. In this paper, volume of fluid method, VOF, has been employed to simulate the free surface flow at the dam bottom outlet form bell mouth section up to the downstream channel. Since the flow through the gates has high Reynolds number, the standard k-ε and also Reynolds Stress Model, RSM, turbulence models is used and the results compared. The discharge coefficient and the ventilated air velocity through the vents is computed numerically and compared with the experimental data. Comparison between the experimental data and numerical simulation results shows good compatibility, especially in RSM turbulence model rather than k-ε turbulence model. The results show that the maximum error percentage in simulation of the discharge coefficient and the ventilated air velocity is 9% and 3% respectively.

Graphical Abstract

Keywords

dor

20.1001.1.22287922.2019.8.2.4.1

Main Subjects

Hydraulic and Pneumatic Systems

References

[1] A. Kalinske, and J. M. Robertson, “Closed conduit flow”, ASCE Transactions, Vol. 108, pp. 1435-1447, )1943(.

[2] H. R. Sharma, “Air entrainment in high head gated conduits”, Journal of Hydraulics Division, ASCE, Vol102, No. 11, (1976).

[3] J. Speerli and P. U. Volkart, “Air entrainment in bottom outlet tailrace tunnels”, Proceedings of the 27th IAHR Congress, San Francisco, Theme D, pp. 613-618 (1997).

[4] M. J. Kenn and A. D. Garrod, “Cavitation damage and the Tarbela tunnel collapse of 1974”, Proc. Institution Civil Engineers, Vol. 70, No. 1, pp. 65- 89 (1981).

[5] J. Speerli, W. H. Hager, “Air-water flow in bottom outlets”, Canadian Journal of Civil Engineering, Vol. 27, pp. 454-462 (2000).

[6] K. H. Safavi and A. R. Zarrati, J. Attari, “Experimental study of air demand in high head gated tunnels”, Journal of Water Management, Vol. 161, (2008).

[7] B. Dargahi, “Flow characteristics of bottom outlets with moving gates”, Journal of Hydraulic Research, Vol. 48, No. 4, pp. 476-482, (2010).

[8] J. Yazdi and A. R. Zarrati, “An algorithm for calculating air demand in gated tunnels using a 3D numerical model”, Journal of Hydro-environment Research, Vol. 5, (2011).

[9] R. Kolachian, A. Abbaspourand F. Salmasi, Aeration in Bottom Outlet Conduits of Dams for Prevention of Cavitation, Journal of Civil Engineering and Urbanism, Vol. 2, Issue 5, pp. 196-201, (2012).

[10] A. Kiczko, J. Kubrak, E. Kubrak, Experimental and numerical investigation of non-submerged flow under a sluice gate, Annals of Warsaw University of Life Sciences, Vol. 47, Issue 3, pp. 187–201, (2015).

[11] S. Y. Kumcu, Investigation of flow over spillway modeling and comparison between experimental data and CFD analysis, KSCE Journal of Civil Engineering, Vol. 21, Issue 3, pp. 994–1003, (2017).

[12] N.M. Nouri, M. Moghimi, S. M. Mirsaeedi, Numerical Simulation of unsteady cavitating flow over a disk, Journal of Mechanical Engineering, part C, Vol. 224, 2010.

[13] B. E. Launder and D. B. Spalding. “Lectures in Mathematical Models of Turbulence”, Academic Press, London, England, (1972).

[14] D. L. Youngs, “Time-Dependent Multi-Material Flow with Large Fluid Distortion”, Numerical Methods for Fluid Dynamics, Academic Press, (1982).

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