Application of VOF and k-ε turbulence model in simulation of flow over a bottom aerated ramp and step structure

Authors

  • Talia Tokyay Department of Civil Engineering, Middle East Technical University, Ankara, 06800, Turkey
  • Can Kurt Department of Civil Engineering, Middle East Technical University, Ankara, 06800, Turkey

DOI:

https://doi.org/10.4314/wsa.v45i2.15

Keywords:

jet-length, aerator, VOF, air-entrainment, ramp, computational fluid dynamic

Abstract

A three-dimensional numerical model of ANSYS, Fluent (2011) was employed for studying mid to high discharge supercritical two-phase flow over a single slope spillway with a single step for aeration of the flow. In this study 18 simulations were conducted using the Volume of Fluid (VOF) method for air-water interface tracking and simple k-ɛ model for turbulence closure. Submerged circular shaped pipes located at the bottom of the step were utilized as aerators. Analyses concentrate on the air-entrainment phenomenon and jet-length of the flow from the step to the re-attachment point. The variables considered in the study are discharge, aerator size, different aerator arrangements, Froude number of the flow, presence of a ramp before the step and its angle. Observed jet-length values in this study were compared with two sets of empirical formulae from literature for code validation. Cross-sectional average of air concentration due to bottom aeration was determined in the streamwise direction downstream of the re-attachment of the jet. The air concentration is observed to follow a logarithmic decay in the flow direction within the de-aeration zone.

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Published

2019-04-30

Issue

Vol. 45 No. 2 April (2019): Water SA

Section

Research paper

License

Creative Commons License

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How to Cite

Tokyay, T. and Kurt, C. (2019) “Application of VOF and k-ε turbulence model in simulation of flow over a bottom aerated ramp and step structure”, Water SA, 45(2 April). doi:10.4314/wsa.v45i2.15.