EXPERIMENTAL AND NUMERICAL SIMULATION OF FLOW OVER BROAD CRESTED WEIR AND STEPPED WEIR USING DIFFERENT TURBULENCE MODELS

A. M. Al-Hashimi, Shaymaa; M. Madhloom, Huda; Nazar Nahi, Thameen

	EXPERIMENTAL AND NUMERICAL SIMULATION OF FLOW OVER BROAD CRESTED WEIR AND STEPPED WEIR USING DIFFERENT TURBULENCE MODELS
Journal of Engineering and Sustainable Development
Article 1, Volume 21, Issue 2, 2017, Pages 28-45
Authors
Shaymaa A. M. Al-Hashimi; Huda M. Madhloom; Thameen Nazar Nahi
Abstract
A broad-crested weir has been considered the most hydraulic structures which was used in open channels for flow measurement and to control the water surface levels due to its simplicity. Both experimental and numerical models were conducted on a broad crested weir and stepped weir with a rounded corner. In this study, FLUENT software as a type of Computational Fluid Dynamics (CFD) model, represented as a numerical model in order to simulate flow over weirs that govern by Reynold averaged Navier Stoke equation and their results were compared with experimental results. The structured mesh with high concentration near the wall regions was employed in the numerical model. The volume of fluid (VOF) method with four turbulence models of Standard k–ε, RNG k–ε, Realizable k–ε and Standard k–ω are applied to estimate the free surface profile. The result showed that the flow over weirs is turbulent and the characteristics of free surface were complex and often difficult to be predicted. Also, the comparison of water surface profile between experimental value and numerical results obtained from the turbulent models showed that the standard k–ε model has the best similarity and standard k–ω model has the minimum similarity with experimental value.
Keywords
Broad Crested Weir; Stepped Weir; Numerical CFD Model; FLUENT; VOF; Turbulent Models

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