I’m performing a Inline Structure with a 109 m length ogee spillway. When the spillway aprox height is 4.00m and the Design Energy Head is 5.00m, the weir coefficient returned by the software is 2.14. I’m working with SI Unit.
With 2,710 m³/s flow, the software return is H=4.67 upstream the inline structure . In this conditions, when the equation Q=C.L.H^1,5 is solved, the C coefficient returned is 2.46, a very height coefficient.
The approximation velocity is 3 m/s for this flow.
Solving the equation with the C coefficient of 2.14, the elevation by upstream is 5.12m. If the Design Energy Head is 5.00m, the result of software should be similar to the one obtained through the equation solution.
I’m not understanding why the software return this value, different to the one I calculated, and I need some help to solve and understand this problem.