Flow over a pipe

[hogart26]

I am trying to calculate the flow depth over a 36-inch pipe embedded in a concrete, rectangular channel for a given flow rate. Upstream of the pipe, the channel slopes from the top of the pipe away from the pipe. Downstream of the pipe, the channel starts at about the centerline of the pipe and again slopes away from the pipe (the channel slopes away from the pipe on both sides of it). Any input would be appreciated.

 

[cvg]

how about critical depth (or very close)

 

[hogart26]

I agree. Thanks for the confirmation (that's what I've done).

 

[gbam]

Why not evaluate a weir over the pipe crown? Since the channel slopes away from the pipe US & DS, the water must reach a level prior to flowing over the top.

If you are RASing the channel run in mixed regime and describe the critical points. Clearly there will be a backwater due to the adverse slope upstream. Am I missing something?