INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING Int. J. Numer. Meth. Engng 2007; 72:221–243 Published online 14 February 2007 in Wiley InterScience (www.interscience.wiley.com). DOI: 10.1002/nme.2016 Numerical modelling of turbulent flow through spillway with gated operation M. R. Bhajantri 1, 2 , T. I. Eldho 1, ∗, †, ‡ and P. B. Deolalikar 2 1 Department of Civil Engineering, Indian Institute of Technology, Bombay, Powai, Mumbai 400 076, India 2 Central Water & Power Research Station, Khadakwasla, Pune, India SUMMARY Numerical simulation of rapidly varied, free surface turbulent flow over spillway with the existence of both sub-critical and super-critical flow regimes is a challenging task. Vertical acceleration plays a dominant role in the spillway flows. This paper describes the formulation and development of a numerical model for flow over the spillway. The computer model is developed using the finite volume method based on weakly compressible flow equations and large Eddy simulation (LES)-based turbulence model. The model is applied to a real world case study of partial gate operation of sluice spillway to investigate the hydraulic characteristics by simulating the velocity distribution, pressure distribution and discharge characteristics. Numerical modelling of sluice spillway is complicated because both moving free surface region and fixed conduit pressure flow in the sluice barrel are present. The numerical model results are compared with the physical model study. The simulated results are in close agreement with the measured values. Copyright 2007 John Wiley & Sons, Ltd. Received 9 July 2006; Revised 14 December 2006; Accepted 11 January 2007 KEY WORDS: sluice spillway; weakly compressible flow; finite volume method; large Eddy simulation; turbulent flow; pressure distribution 1. INTRODUCTION Spillway is a hydraulic structure provided at the dam to release floodwater that cannot be stored safely in the reservoir. Various hydraulic design aspects such as discharging capacity, pressures and water surface profiles and energy dissipation arrangement are considered to evolve hydraulically efficient design of spillway. Size of the spillway plays a major role in the economic analysis and safety of the dam. Normally, a narrow spillway with higher discharge intensities would be less ∗ Correspondence to: T. I. Eldho, Department of Civil Engineering, Indian Institute of Technology, Bombay, Mumbai 400 076, India. † E-mail: eldho@civil.iitb.ac.in ‡ Associate Professor. Copyright 2007 John Wiley & Sons, Ltd.