Intake is an open channel that usually has a non-uniform flow along its length. The
pattern of the flow in lateral intakes is fully three-dimensional. That is why many
studies were carried out on the flow characteristics at the intakes. Velocity and
direction change in lateral intakes lead to non-consistency and recirculation of the
flow. As the result of these whirlpools, depositions are accumulated inside intakes
which consequently decrease intake efficiency. High maintenance cost is regularly
paid in order to dredge the sedimentation areas and to guarantee and maintain
efficiency. The aims of this study were to get a suitable design of the lateral intakes
to improve the flow characteristics at junctions. This study is conducted by using a
numerical Software Delft3D-FM which used in predicting flows pattern which
validated and employed in a parametric study. The model dimensions were
assumed based on a real project data at Nile River in Assiut, Egypt. In this study,
four models with sharp edges and different bed levels were presented to investigate
flow separation zones at different angles of the intake entrance. In order to control
the model accuracy in predicting the dimensions of the separated areas, the results
were compared with the base configuration which has a flat horizontal bed level of
intake. Comparisons between the predicted and the initial configuration velocities
at the considered sections indicate that the model captures most of the trends with
sensible accuracy. It is concluded that configuration number 4 which has two-fold
baffle walls located on the right side has a significant effect on improving flow
velocity, circulation zone length, reverse flow width as it enforces the flow to the
inner side achieving a good flow distribution inside the intake. The results indicate
also that the optimal angle of lateral intake which gives minimum length and width
of separation zone is at θ = 30°. |
