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Hello,

I am quite new to the Telemac2d system and I am using it for my master thesis. For the beginning I should be investigating the wind effect on some simple geometry coastal basins as shown at the attached picture.

The problem is that according to the situation the North, East and south boundaries should be open with the control of water level as a boundary condition. but whenever I define the water level boundary condition at the 3 boundaries the results seems to be either overestimated or unstable as you can see from the attached picture.

Whenever I try to totally close the eastern boundary and define it as a wall the results seem quite fine but it is not the case that I need to model.

my wind velocity is 10 m/s

Do you have any experience or suggestions with such a problem with multiple connected boundaries ?

Hello

Actually your 3 open boundaries constitute one large open boundary, on which you want to prescribe a constant elevation of 3m everywhere. This looks a bit strange, at least it is unphysical since wind is supposed to generate a current that is supposed to make non negligeable variation of the water elevation.

It goes better with a lateral wall condition, since the the current will enter from south and leaves from nothern boundary.

If you want to stay with 3 open boundaries, first unify them into one unique boundary and then use Thompson boundary condition. It should work well.
Finally, I do not have any idea about the extend of your model, however, if it is coastal case, you should rather use tide to prescribe you open boundary conditions.

I hope that this helps

with my best regards

Riadh ATA

Hello,

thank you Riadh for the answer.
We are working together at this case and I am not familiar with the Thompson boundary condition. I saw that there are 2 options, which would you use? Should one also add a liquid boundary file? Are there some examples about it?

Thanks.

Best regards

Hello

There is only one option to trigger the Thompson boundary conditions. You need to use the following keyword OPTION FOR LIQUID BOUNDARIES=2
From a user point of view, boundary is handled as a standard liquid boundary (with prescribed values, liquid boundary file, etc.) there are no additional treatment for Thompson condition. Telemac will prescribe the smartest condition in accordance with mathematical properties of the used equations.

with my best regards

Riadh ATA