NUMERICAL SIMULATION OF WATER FLOW ALONG STEPPED SPILLWAYS WITH NON UNIFORM STEP HEIGHTS

C. BENTALHA, M. HABI

Abstract


Stepped spillway is a good hydraulic structure for energy dissipation because of the large value of the surface roughness. The performance of the stepped spillway is enhanced with the presence of air that can prevent or reduce the cavitation damage. The flow over a stepped spillway can be divided into nappe flow regime, transition flow regime and skimming flow regime. This study aims to investigate the effects of the non uniform step heights on the air-water flow properties at stepped spillways. The numerical results of air concentration, air_water velocity and turbulence kinetic energy are presented in this research. Within this work flow over stepped chute is simulated by using fluent computational fluid dynamics (CFD). The volume of fluid (VOF) model is used as a tool to simulate air-water interaction on the free surface thereby the turbulence closure is derived in the k −ε turbulence standard model. The found numerical results agree well with experimental results.


Keywords


air-water flow, Fluent, VOF Model, Stepped Spillway, Standard k −ε Model.

Full Text:

PDF

References


AFSHIN EGHBALZADEH, MITRA JAVAN, 2012. Comparison of Mixture and VOF Models for Numerical Simulation of Air–entrainment in Skimming Flow over Stepped Spillways .J. of Science Direct. Procedia engineering (28) 657 – 66.

BENMAMAR, S. KETTAB, A., THIRRIOT, C., 2003, Numerical simulation of turbulent flow upstream of the inception point in a stepped channel. Proceedings, 30th IAHR Congress. Auth, Thessaloniki, Greece: 679-686.

BOMBARDELLI FA, MEIRELES I, MATOS J, 2010. Laboratory measurements and multi-block numerical simulations of the mean flow and turbulence in the non-aerated skimming flow region of steep stepped spillways. Environ. Fluid Mech 11(3):263-288.

CHANSON, H, 1997. Air Bubble Entrainment in Free-Surface Turbulent Shear Flows. Academic Press, London, UK, 401 pages ISBN 0-12-168110-6.

CHANSON, H., 2001. The Hydraulics of Stepped Chutes and Spillways. Steenwijk, the Netherlands: A. A. Balkema Publishers.

CHANSON, H., TOOMBES, L. 2004. Hydraulics of stepped chutes: the transition flow. Journal of Hydraulic Research, Vol 42, N°1, pp 43–54.

CHARLES E.RICE, KEM C.KADAVY, 1996. Model of A roller compacted concrete stepped spillway. Journal of Hydraulic Engineering, ASCE, 122(6):292-297.

CHEN, Q., G.Q. DAI AND H.W. LIU., 2002, Volume of Fluid Model for Turbulence Numerical Simulation of Stepped Spillway Over Flow. Journal of Hydraulic Engineering, ASCE 128 (7): 683-688.

CHINNARASRI, C., KOSITGITTIWONG, K. JULIEN. PY. 2012. Model of flow over spillways by computational fluid dynamics.Proceedings of the Institution of Civil Engineers, pp 1-12

CHRISTODOULOU, G.C. 1993. Energy dissipation on stepped spillways. Journal of Hydraulic Engineering, ASCE 119 (5): 644-650.

FELDER, S. 2013. Air-Water Flow Properties on Stepped Spillways for Embankment Dams: Aeration, Energy Dissipation and Turbulence on Uniform, Non-Uniform and Pooled Stepped Chutes. Ph.D. thesis, School of Civil Engineering, The University of Queensland, Australia.

FELDER, S., CHANSON, H. 2011. Energy Dissipation down a Stepped Spillway with Non- Uniform Step Heights." Journal of Hydraulic Engineering, ASCE, Vol. 137, N° 11, pp. 1543- 1548 .

Fluent, 2006, Manuel and user guide, Fluent Inc

IMAN NADERI RAD, MEHDI TEIMOURI., 2010. An Investigation of Flow Energy Dissipation in Simple Stepped Spillways by Numerical Model. European Journal of Scientific Research. ISSN 1450-216X Vol.47 No.4:544-553.

MOHAMMAD S, JALAL. A., MICHAEL. P, 2012. Numerical Computation of Inception Point Location for Steeply Sloping Stepped Spillways” 9th International Congress on Civil Engineering, Isfahan University of Technology (IUT), May 8-10,Isfahan, Iran

RAJARATNAM, N, 1990. Skimming flow in stepped spillways. Journal of Hydraulic Engineering, ASCE 116 (4): 587-591.

STEPHENSON, D. 1988. Stepped Energy Dissipators. Proc. International Symposium on Hydraulicsfor High Dams, IAHR, Beijing, China, pp. 1228-1235.


Refbacks

  • There are currently no refbacks.


Creative Commons License
This work is licensed under a Creative Commons Attribution 3.0 License.