Numerical and experimental study of flow pattern at the junction of 90o rectangular channels

In this paper flow pattern at 90o, rectangular channel junctions have been studied. Flow pattern in open channel junctions was studied both experimentally and numerically. Velocity measurements were taken using an acoustic doppler velocimeter and depth measurements were made using a point gauge over a grid defined throughout the junction channel region. Velocity distribution in various plates for six discharges ratio Q* was investigated. Results showed that there is a good agreement between the model simulation and the experimental measurements. Both experiments and numerical model showed that by combining two flows in the main and lateral channel, producing a helical flow in the main channel affecting flow pattern. This helical flow formed a separation zone at downstream of lateral channel and this separation zone affecting by discharge ratio. This zone has an inclination to the main right wall at upper layer and in lower layer has an inclination to the left wall. When decreasing Q* separation zone is also decreased in width and length. Longitudinal and vertical velocity vectors in the main channel have small magnitude at upstream main channel. By combining the lateral flow and main flow increasing the magnitude of transversal velocities results also indicate that maximum transversal velocities occur at maximum contraction of flow.