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Re: duck bill
Hello,
You want to know the WS elevation upstream the weir, so you can limit your model to the part upstream the weir, finishing it at the weir station. Doing that, your downstream boundary condition is the height vs discharge law of the duck bill.
So you can now introduce point by point a law of the following type as a rating curve in the boundary conditions interface :
Q=Cd.L.sqrt(2.g).h^3/2
where Cd is the discharge coefficient (around 0.4), L the crest length, g the acceleration of gravity (9.81 m/s^2 in metric system) and h the water height above the crest. All units are in the International System.
You can of course use another law.
Sincerly,
YV.
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