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Hi Everyone,

I have few questions in the Telemac2D_user manual in weirs (Section 13.1).
From where did the equation for submerged and unsubmerged weir come?
Is it Poleni's equation and if not is there a reference for it?
If possible I want to have a little more explanation for the equation of "the weir is not submerged if:"

Kind regards
Sandip

Hi
Yes it's the well know Poleni equation

For the equation of "the weir is not submerged if" there is a typing error in the document (thanks for pointing this)
the right equation is:
downstream level < .....

Hope this helps

Hi

This helps a lot.

Poleni equation consider the width of weirs. I did not find this in the manual and the subroutines (LOIDEN and LOINOY) also. Is it considered 1?

Kind regards
Sandip

Hi
The computation is done without the length because this is implicitly given by the boundary length as the weirs is supported by a boundary

Hope this helps

Hi again,

I did not mean the longitudinal length of the weir rather the width of the weir.

I have attached two screenshots to explain. The equation is Weirs equation where
Q is the discharge, Kw is the dimensionless coefficient of discharge, ho is the head over the u/s weir crest to the free surface and Lw is the width of the weir as shown in figure. My question is where is this Lw (width) parameter considered?

Kind regards
Sandip

As I already wrote,
A weir is described by boundary nodes (same number upstream and downstream) and of course this implicitly means you have at least 2 nodes upstream and 2 nodes downstream to define a liquid boundary.
Then this is the length of the boundary which is the length Lw...