A. Shamsai, R. Soleymanzadeh,
Volume 4, Issue 1 (3-2006)
Abstract
Flow regime in dam's bottom outlet is divided in pressurized flow and free surface flow by
the gate located for discharge control. Down stream tunnel involves high velocity Multi component
Air –water flow studied by mathematical model. In this research work, we used Finite volume
mixture two phase flow model. Because of high Reynolds number, standard two equations k-e
turbulence model was used. Model was verified by backward-facing step flow and results have been
compared with experiments founded by Durst and Schmitt. Air demand ratio has been determined
as function of Froude number at contracted section. Flow patterns have been compared at two
categories of slug & stratified flows, Air mean concentration profile has been obtained at down
stream tunnel. Comparison of flow pattern at two case with and without of aeration was
investigated. Pressure drop behind of the gate and formation of vortex flow after the gate section
have been discussed. Measurement of flow discharge and determination of contraction coefficient
of the gate was outlined.