Effect of Main Channel Roughness on The Branching Flow

Abstract

The work concerns a laboratory study to investigate the effect of changing the bed roughness of the main channel on the branching discharge and separation zone formed in the main channel as a result of discharging flow through a branch channel. The ratio of main channel roughness to the roughness of the branch channel bed has been changed between (1.7-3.9) for two branching angles (30˚, 90˚) and for different values of main channel discharge ranged between (7-17) L/sec. Laboratory result shows that branching discharge ratio increases by the increasing the total discharge through the main channel at roughness ratio less than (2), where's the branching discharge decreases at roughness ratio greater than (2), and stay constant at roughness ratio about (2) for all discharge passing through the main channel. The result shows that the length of the separation zone decrease with the increasing in the roughness ratio and total discharge through the main channel.

A Review of Studying the Flow Characteristics in Branching Open Channels

“…Hager [26], Kesserwani et al [27] and Ghostine et al [28] investigated their empirical equations for treating flow branching as a side flow over from side weirs zero high. Most of the flowing to the Branching channel would be studied with a right-angle branching and a rigid boundary, while a few researchers have studied by using different branching angles [29][30][31] or/with a condition of bed movable [32]. Herrero et al [9] discovered a scour hole formed at the edge downstream to the entry of the branch channel in a diversion flow with (900) branching flow and a bed of movable sand.…”