Main Article Content
Numerical simulation has been carried out to observe and predict the mechanisms of stationary mixed flows in a free surface channel combined with a closed conduit. This study has been conducted with a wide range of discharge values, based on a free rectangular channel (4.5x0.98x0.50 m) at the upstream combined with a closed rectangular conduit (4.5 m length), located at the end of the channel. The height of the conduit is fixed at 100 mm and the conduit width is varied to form several other geometrical configurations. From the obtained numerical results, the local head losses at the transition location are computed and a relation between the local head loss coefficient at this transition and the water depth at the upstream free surface channel is proposed. It will be verified by experimental results in the next study.