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Hi dear Telemac users,

I am currently working on a simulation where I have to use both tides and an additional surge that comes from a larger scale model. This surge will be time varying but considered constant on all my liquid boundary. I've ran some tests and it seems that if I use tpxo tides in my simulation I cannot modify the water level afterwards.
I tried to modify the water level using PRESCRIBED ELEVATION , a LIQUID BOUNDARY FILE , the user_sl.f subroutine and even tried to modify the pressure value to create the surge. But none of this worked.
If I remove the tide forcing I can modify the water level, but the tide is really important in my case.

To run my tests I used the telemac2d/tide example, you will find attached my .cas file and the liquid boundary file that I created for this test. If you want to try my simulation you should already have the geo and cli file as they are those from the tide example, you will only have to download the binary data files "hf.ES2008.out" and "uv.ES2008.out" from "people.oregonstate.edu/~erofeevs/ES.html".
I am using Telemac2d v8p2.

I have not found any posts on this forum that deal with this subject and I apologize if there already is one.
I would be glad if anybody could help me with this issue.
Cheers,
Thomas

Hi everyone,

I worked on my issue and finally found a solution that seems to work.

I realized that the keyword "coefficient to calibrate sea level"(=MSL in fortran code) existed and allows us to modify the sea level even with tides. But this coefficient is not temporally variable. So I added to the tidal_model_t2d.f file a little code that gets from the "formated data file 2" the temporally variable sea level and interpolates it at each timestep. This new interpolated sea level coefficient is called MSLT and replaces MSL in the calling of BORD_TIDE_TPXO.

I am NOT a FORTRAN expert, but this solution seems to work(only if I use tpxo tides) and it is not thoroughly tested yet. You will find attached my tidal_model_t2d.f file.

I hope this work will help someone.

Thomas

Hello Thomas,

Thanks for your suggestion.

I think you can also solve this by changing 2 lines at the end of the tidal_model_t2d subroutine:

Rather than:
HBOR%R(K) = HBTIDE%R(K)
H%R(MESH%NBOR%I(K)) = HBOR%R(K)
Write:
HBOR%R(K) = HBOR%R(K) + HBTIDE%R(K)
H%R(MESH%NBOR%I(K)) = H%R(MESH%NBOR%I(K)) + HBOR%R(K)
if you give a LIQUID BOUNDARIES FILE containing the storm surge water elevation (as many columns as the number of tidal boundaries).

Indeed, the current computation of tidal boundary conditions overwrites what is done before for water depth and velocity prescribing.

Anyway, do not forget the new feature #REFDATE (see the user manuals for release v8p2) that enables you date and hours that will be automatically added to the times in ASCII files like LIQUID BOUNDARIES FILE, ASCII ATMOSPHERIC DATA FILE etc. It may help you if you change the date of start of the computation for these kinds of files.

Hope this helps,

Chi-Tuan

Hi everyone,

Thank you Thomas and Chi-Tuan for posting these two quick fixes!

I didn't think of solving this problem using that FORTRAN file!

I had a go with Chi-Tuan's approach, however, I believe it needs a small tweak.

To add the surge levels from your LIQUID BOUNDARY FILE, it seems you can indeed replace the line:

HBOR%R(K) = HBTIDE%R(K)

But, you need to remove the water depth too:

Z_BAC=ZF%R(MESH%NBOR%I(K))
HBOR%R(K)=HBOR%R(K)+HBTIDE%R(K)+Z_BAC

And it seems to work.

Hope that helps a little!

Rgds,
Baptiste