Flow resistance and velocity distribution in a smooth triangular channel

Abstract

This study investigates the flow resistance and velocity distribution in a smooth triangular channel under varying slope conditions in a laboratory environment. For this purpose, two triangular cross-sectional shaped channels with 30° and 45° sidewall slopes were made. In various hydraulic conditions, bed slopes were carried out at different flow discharges and channels. The results have been used to test the stage-discharge curve, Manning roughness coefficient, n, the Darcy-Weisbach friction factor, f, and flow velocity profiles. By increasing the channel bed slope and flow discharge, the water surface fluctuation increased simultaneously. The fluctuation of flow surface profile in the triangular cross section (TCS) at 45° is more than in TCS 30° cases. The stage-discharge rating curve has less curvature with increasing channel bed slope. The Darcy-Weisbach f obtained from TCS 30° is higher than for TCS 45°, which means that TCS 30° has more resistance against flowing water passing through the channel than the 45° cross-section. Examination of the velocity contours shows that the maximum velocity occurred in the 30° triangular cross-section. Practical-sound findings from this research might be helpful for hydraulic engineers to design cost-effective open channels and other similar hydraulic structures. HIGHLIGHTS The fluctuation of the water surface profile with triangular cross section (TCS) 30° was higher than for TCS 45°.; By increasing the slope of the channel, the Darcy-Weisbach (f) increases. The f obtained from TCS 30° is higher than that of TCS 45°.; With an increase in the channel bed slope, the longitudinal component of velocity increases. Furthermore, the maximum velocity occurred with TCS 30°.;

Keywords

• friction factor
• manning's roughness
• open channel
• stage-discharge relationship
• velocity contour