open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,

I would like to simulate a flow under a small bridge, and thus, I use the TUBES DATA FILE.
I understand and know all the input data, like the head loss coefficient etc. except these ones: z1 and z2.
The description in the manual says that these are the level of the tapers. What does that mean? Is this the absolut height of the entry point and of the exit point? Or is this not necessary, because of the fact that one has to enter the point coordinates, does Telemac already have the height cooerdinates?
In addition to this, in the bridge example, z1 and z2 are also both set as 1, but the bathymetrie in that example is not 1.

Thanks in advance!

Regards.

Hi
Z1 and Z2 are the bottom level at the entry/outside of the tube. They exists mainly because some tubes/bridge often have a concrete structure on the bottom which is sometimes higher than the bottom level of the river and then this could work as a weir for very low water depth.
It seems to me that there is a security in the code to check that this level is at least higher than the bottom level at the entry/outside node

Regards

Hello Mr. Coulet,
thanks a lot for your quick reply!

I did some test cases where e.g. my inlet point is of 309.4 m height an my outlet point ist of 307.3 m height.

So if my Z1 is equal to 310.4, this means that water can only enter the tube at height 310.4?

If I set Z1 and Z2 below the bathymetrie of the studied area (in this specific case e.g. Z1 = 0, Z2 = 3), they are not considered at all? Then, if there is no specific structure on the bottom at the inlet or outlet, I can just leave Z1, Z2 equal to 0, 1, 10 or whatever... so Telemac uses always the bathymetrie heights (as gathered from the coordinates) as minimum heights for the inlets and outlets.

So, it's not like the bottom levels of the inlets and outlets are added to the bathymetry height.

One more thing, is the formula for the tube discharge identical to the one for the culvert discharge?

Thanks a lot!

Regards