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Hello,

I would like to know what is the influence of the parameter "depth in friction terms"? Particularly, what is the option 2 "average" (the principle)?

Thank you

Hello,

In friction formula we have the depth in the denominator. You can consider the local value at a point (option 1) or an average value around the point (2). It may have an influence with tidal flats, and the second option would be better, but there is no real validation study showing the advantages of both options, and the friction terms being highly non linear many other variants could be imagined.

With best regards,

Jean-Michel Hervouet

Thank you.

But I am not sure why the option 2 would be better. It's in case of tidal flats but is it for the specific points in the illustration that I joined (points at the down of the embankment for example)?
Because in this case, for the option 2, the depth is lower so the friction coefficient is higher, which is maybe more consistant because of the change of slope. Is it the interest of this option?

Thank you

Hello

The case of point at the down of an embankment can be retrieved elsewhere in the domain and that's why it is not the interest of this option.
As already said by Jean Michel (Hello from Chatou ), this non linear term can be treated by many other ways. The interest of option 2 is mainly to smooth the strong non linear effects when the water depth at the node goes to zero. The use of an everage of the water depth around the node will have more "dumping effects" especially for tidal flats fronts. However, it could change the friction effects for completely wetted areas.

With my best regards

Riadh ATA