open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello,everyone.

I'm new for using telemac2d and got a lot of hints from here recently.

Thank you for your sharing.

Now I have a problem. Here it is:

I am using telemac2d to simulate the current of some coastal area, which has

one solid boundary and three open boundaries.

I want to give tidal elevations to the 3 open boundaries by using the subroutine BORD(according to user mannual), but I don't where to begin with?

Could someone give me some idea about that?

Thanks in advance.

Hong

Hello,

Provided that your boundary points are declared as prescribed elevation (lines beginning by 5 in the boundary conditions file) you can add function SL (from library telemac2d) in your FORTRAN FILE and program it as a function of the point number.

However it is not sure that your problem will be well posed, and you may have to use the Thompson boundary conditions (OPTION FOR LIQUID BOUNDARIES : 2;2;2... as many as liquid boundaries)

With best regards,

Jean-Michel Hervouet

Dear Jean-Michel Hervouet,

Thank you for your early reply .

I think I didn't make my problem clear.

I know SL function can be used for boundary condition which is constant in space but varies in time.

But I plan to use boundary conditions which varies both spatially and temporally.

So would you please explain again how to give the water lever open boundary condition using BORD subroutine?

Best wishes

Hi,

What do you mean by "boundary conditions varing in space and time"? Do you mean:
1- your domain in varying in time and the boundary nodes are changing during the simulation
2- Your domain is not changing but boundary condition types are changing during the simulation i.e. a liquid node can change to solid wall node and vice versa?

In a classic way, to prescribe tidal elevation, you need to proceed like explained in last post i.e. using SL subroutine combined with a Thompson condition. As you are a new Telemac user, it is safer to start with this classic way.

With my best regards.

Riadh

Hello, riadh.

Thank you for your discussion with me.

The changing boundary condition I mentioned last time doesn't refer to the change of boundary condition type, but means" the tidal elevation varies from node to node in each open boundary and varies from time to time meanwhile."

So do you think if I should still take the same advice from Jean-Michel and you,i.e. using SL function combined with a Thompson condition?

Best wishes

Hi again,

This exactly what I meant by 'classical' way. You have the possibility to prescribe the elevation node by node (using a loop over boundary nodes).
You can give a glance to the validation cases "Tidal flow in the Mersey estuary" or "western European continental shelf" where the tide effects are taken into account. That could help you to go on with your model.

All the best,
Riadh

Thanks a lot, Riadh.

I got it.

Have a nice day:P

Hello,everyone.


I'm making my effort to do that way you suggested.

However,I still have a question,that is

Since SL function can provide elevation, what's the use of the subroutine TIDAL_MODEL_T2D() in bord.f?

Look forward to your reply.

Hello,

As you may see by yourself, the subroutine TIDAL_MODEL_T2D is used to prescribe tidal boundary conditions with a specific tidal constituents database. This is a specific treatment, not a general one as you can do with SL function.

I continue the discussion in your post with fort.14

Chi-Tuan

Hi,there.

I met a new problem again.

As you suggested in former posts, I used SL function to provide tidal evelation to every node on the liquid boundary. There are totally 107 nodes.
But it is found the information of lots of points ( LIQUID BOUNDARY: SL() = ) missed in the print out file.

I checked the READ_FIC_FRLIQ subroutine and found the result is not reasonable.

Is this problem related to the 99 boundaries limit?

Any help would be appreciated.

Best wishes.