Author(s): Mrs. Prajakta P. Gadge; Prof. V. Jothiprakash; V. V. Bhosekar
Linked Author(s): V. Jothiprakash
Keywords: Sharp edged orifice; Orifice spillway; Physical model; Computational Fluid Dynamics
Abstract: Orifice spillways are extensively used for dual function of flood disposal and flushing of sediment from the reservoirs. However, not much literature is available on the design of orifice spillways. The basic theory of flow through orifice available in literature discusses only the coefficient of discharge and the general parabolic profile of the nappe. As no information is available on the upper nappe of flow, this literature cannot be used directly for the design of spillway. Physical models are being used extensively to understand the complex flow problems. The recent development in computers provided the various Computational Fluid Dynamics (CFD) codes for modeling the complex flow problem in open channel flows. Hence basic research work has been taken up on this aspect by using both physical and numerical models. This paper discusses the simulation of flow through a sharp edged orifice using computational fluid dynamics (CFD) code FLUENT version 6.3. 26. Verification and validation are the primary methods for building and quantifying the confidence between modeling and simulation. The numerical model is verified in terms of grid convergence based on the ASME editorial policy statement, which provides a framework for computational fluid dynamics uncertainty analysis. Various k-εturbulence models (Standard, RNG, and Realizable) were used to determine the sensitivity of results. The Modified High Resolution Interface Capturing (HRIC) scheme of the VOF method was used to compute the water surface profiles. The results obtained from the numerical model were validated with the physical model data in respect of coefficient of discharge and water surface profiles. It was found that the results computed from RNG turbulence model with HRIC VOF scheme were closer to the results of physical model.