open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello all,

The functionality to impose boundary conditions to a nested model from an encompassing one seems to be in place but is undocumented. The preparation of the BINARY BOUNDARY DATA FILE is done using the 'convert_to_bnd.py' script in 'pretel'.
The problem lies with imposing the boundary file to the nested model, where OPTION FOR LIQUID BOUNDARIES does not seem to give the expected results. OPTION FOR LIQUID BOUNDARIES = 2 (Thompson BC) gives results that are similar to the encompassing model:



OPTION FOR LIQUID BOUNDARIES = 1 (Imposed) on the other hand looks like this:


One would expect (according to the encompassing model) water flowing in but right at the boundary the arrows point outwards. A check with the Selafin and TelemacFile classes shows that velocities in the BOUNDARY FILE are as expected.

I am using the trunk. Boundary conditions are set to 566. I attach my T3D steering file:



Best Regards,
Costas

Hi Costas

As far as I know, this functionnality is only available for Tomawac to impose boundary spectra.
You could manage the preparation of a binaly boundary data file but there is no already programmed solution to impose this for hydrodynamics...

I already managed to adapt this solution to impose wave data from ECMWF wave results but not yet for hydrodynamics.
But I'm quite sure it's not a really complex task to achieve

Regards

Hello Christophe,

According to a private communication with Chi-Tuan regarding the user manual, this functionality is implemented but not thoroughly tested, thus not documented yet. Subroutine 'READ_BIN_FRLIQ' is supposed to read from that file and 'BORD3D' calls it.
So, I had reasonable grounds to give it a try and share my findings to help evaluate it.

Costas

Doing some more testing, it appears that having set a BINARY BOUNDARY DATA FILE does not make any difference. The runs with and without one, are completely identical. Although it is read by the code, it seems the data gets overwritten later on.

The strange thing is that without a BINARY BOUNDARY DATA FILE and imposed boundary conditions (OPTION FOR LIQUID BOUNDARIES = 1), the boundary velocities should be zero, as prescribed in the CLI file. However, they are not. They take some values not set by me (intentionally at least).

Costas

P.S. The steering file I attached in the previous post has COMPUTATION CONTINUED, but that is not the case. I mistakenly uploaded the steering file that picks-up from where the discussed computation ends. The rest of the settings are the same.

Hello all,

I did another test, giving up on the BINARY BOUNDARY DATA FILE and instead prescribing WATER DEPTH, U and V velocities through the CLI file.

I set:
OPTION FOR LIQUID BOUNDARIES = 1
VELOCITY PROFILES = 2 for U,V prescribed in CLI

The results I got are identical to every result I get when setting OPTION FOR LIQUID BOUNDARIES = 1.

So this is something other than the initial subject of this topic, which in the end proved to be the new TOMAWACT3D coupling. When enabled, it seems to override the boundary conditions defined in Telemac3D.

I did a run with plain TOMAWAC coupling with boundary conditions defined in the CLI and the results were as expected. On the other hand, I am having trouble with the BINARY BOUNDARY DATA FILE, which brings us back to the original subject. I am working on it and will update with my findings.

Best Regards,
Costas

Hello,

As already discussed with Costas, a fix have been pushed for the trunk version (r15075), there are no overwriting of BC with unexpected values when coupling TELEMAC-3D with TOMAWACT3D.

Anyway, if willing to use BINARY BOUNDARY DATA FILE, currently, you have to also use PRESCRIBED ELEVATIONS and PRESCRIBED VELOCITIES keywords (and PRESCRIBED VALUES OF TRACERS if any) in the steering file with at least as many values as the number of liquid boundaries for the elevation and velocities, and at least as many values as the product number of tracer(s) times the number of liquid boundaries, as described in a new subsection of the TELEMAC-3D user manual (trunk version), see enclosed file.

Chi-Tuan