Investigation of Flow Hydraulics in Flooded Meandering Rivers under the Effect of Floodplain Width Change

Abstract

Flood plains of rivers play a significant role in the transfer of flood discharge. In this research, the vertical distribution of the longitudinal and transverse flow velocities and the amount of discharge passing through different sections of the main channel in flooded meandering rivers under the effect of the change in floodplain width and relative depth were investigated. Because the fact that the width of the floodplain is constantly changing along the river's path, in this article, from the four meandering compound channels with floodplain widths of 3.3, 4.31, 5.32, and 6.33 meters and three relative depths of 0.26, 0.35 and 0.45 were used. The results of the numerical simulation showed that with the increase in the width of the floodplain, the value of longitudinal and transverse flow velocities decreases and these changes in the transverse and longitudinal flow velocities are more noticeable due to the change in the width of the floodplain in the middle sections and above the overflow depth of the main channel, so that with the increase 92% of the width of the floodplain, the value of the maximum transverse and longitudinal flow velocity in the middle section decreases by 21% and 25%, respectively. Also, according to the results of this research, with a 92% increase in the width of the floodplain, the average flow velocity and discharge through different sections of the main channel will decrease by 24% and 33%, respectively.

Keywords

• meandering compound channel
• longitudinal velocity
• transverse velocity
• floodplain width change
• numerical simulation