Document Type : Original Article

Authors

• nilufar kianersi ¹
• mahmood shafai bejestan ²

¹ master student of water structure in shahid chamran university of ahvaz

² professor Dept of hydraulic structure college of water science engineering shahid chamran university ahwaz iran

Abstract

By entery of pollutants into the canals and rivers along a certain distance (Mixing length), the pollution due to factors such as the molecular motion, turbulence and vertical distribution of flow velocity are distributed throughout all the cross sections. There are several techniques to achieve this goals including increasing  cross-mixing. In this study, the application of submerged vanes mounted on the bed of the channel at a certain angle for the purpose of increasing the transverse mixing in a straight rectangular flume was investigated. The experiments are conducted for four different flow conditions including with and without structure. Salt solution as a tracer, was entered to the center of the flume with constant flow rate. The concentration of tracer in four stations downstream of tracker, were measured with EC meter. The results showed that the mounted submerged vanes caused an increase in transverse mixing coefficient of about 1.5 to 1.7 times as compared with the case of no vane. Also, it was found that increasing the rate of flow discharge in case of no vane caused an increase in the transverse mixing coefficient of  about 2.4 times. Similarly, an increase   in the rate of flow discharge with structure caused the increase in the transverse mixing coefficients of about 2.5 times. Generally, the results showed that submerged vanes were very effective on Transverse mixing coefficients.

Keywords

• Submerged Vanes
• Transverse Mixing Coefficients
• Turbulence