open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear all,

I am interested in 3d velocities at a certain point in an estuary.
For this I plan to setup a 3d model for the respective river setion (~ 5km).
As downstram BC I have waterlevels and as upstream BC I have waterlevels and 2d (dephtaveraged) velocity from a gauging station.

My questions:
1. As it is recommended not to use 2 waterlevel BCs I would chose the velocities+waterlevel as upstream BC. Due to tidal influence I have bi-directional flow directions. Especially at the turning points (ebb to flood) I have for some time still ebb flow at the banks while I have already flood flow in the main part. Can Telemac3d deal with this?

2. At the banks of the whole sections I have tidal flats. As I understood, it should be avoided that nodes at open boundaries get dry. So I have to create an inflow and outflow area without that tidal flats, right?

Best regards

Hello,

About 1) for your upstream boundary, you could impose both -- use Thompson boundaries -- although it would be better if you multiply your h by you u,v, integrate over your upstream cross section to make this a bi-directional Q (+ entrance, -exit). The let TELEMAC do the rest (use velocity profile 4 for that boundary).

About 2) for your downstream boundary, you can still set the level even if is it dry. It will create a warning. Just make sure that the level set is not less than your BOTTOM variable (ZF). I would also use velocity profile 4 for that boundary as well.

Hope this helps,
Sébastien.