open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear Users,

I have a quick question and wonder if somebody could point me into right direction. I am testing some tidal TPXO files and they seem work ok. My initial condition is TPXO SATELLITE ALTIMETRY, so I cannot specify initial conditions as constant depth or constant elevation. Since it is just a testing then I do not have various depth bathymetry. It is just a tank with constant depth, everywhere 900m. I used Condim subroutine where I would normally specify the domain depth. Now I have the Tidal_Model_T3d subroutine. I have prescribed depth in Boundary condition file as HBOR set to 900 but it looks like is not picked up from there. I have tried to add Condim subroutine to the Tidal_Model_T3d subroutine but it is not working either. Is there is any more ways to specify the depth of water, as at the moment I have very low various levels and water depth have the same results as surface elevation. Thanks in advance.

Kind Regards!

Violeta

Hello Violetta,

You can implement whatever you want in TELEMAC, as it is open source. In TELEMAC-3D, the boundary conditions are calculated in the BORD3D subroutine. You can prescribe what you want, comment or delete some lines...

You describe a schematic tank and would like to use an harmonic constants database, but not to prescribe water depth at the liquid boundary, do you? It is not clear to me what you try to do with real data (TPXO) and a schematic tank (do you declare a geographic system in order to use the harmonic constants database?).

Anyway, I hope this can help you.

Regards,

Chi-Tuan

Hello Chi-Tuan,

Thanks for your reply. I cannot get a good bathymetry (this case is on Greenland fjord) on my region at the moment, so I decided, in mean time, to apply some tide on hypothetical area, some shape like a rectangle tank. It has to be 900m deep. But I think that in order to use the harmonic constant I still have to have correct geographic location, even it does not have a real bathymetry, dont I? So I need the tank to be located on relevant to this region coordinates (translated in Cartesian) and under correct angle.
For other cases I run on simple shape like a tank for stratification, I used CONDIM subroutine and there I could specify the water depth. When I added this subroutine to the Tidal_Model_3d, it provides the required depth in domain but not at the boundary. I will prescribe it in Selafin file shortly and will check if it fix the problem. Also I will use BORD as you recommended. Thanks for your advice. I will come back if it is not working with more clear questions. Thanks again.

Kind Regards!

Violeta

Harmonic constants are only dependent on the location, you must be accurate to locate the liquid nodes.

CONDIM subroutine computes the initial conditions and is used to give data to build the vertical mesh whereas BORD3D computes the boundary conditions, this is different.

Hope this helps,

Chi-Tuan

Thank you very much Chi-Tuan. I will follow your advice. Thanks again.

Kind Regards!

Violeta

Hello Chi-Tuan,

I am still confused where in BORD3D I can specify the water depth at the open boundary. I used CONDIM for initial conditions, the water depth works fine at the beginning of calculations (900m)but dramatically reduces when tide comes into domain (down to 50m!!!). I am not sure what field to modify in BORD3D, whatever I change does not improve the simulation. Sorry I am not proficient with Fortran yet, but one day I hope I will be:). Thank you.

Kind Regards!

Violet

Hello Chi-Tuan,

Thank you very much with your help on JMJ data download. With your trick to add -h to the run it worked fine. Thanks again.

Just to come back to my old problem with water depth in the tank. I made some changes in BORD3D but it is still not working. Basically I have a tank, in correct geographical location what I downloaded tidal data for, with depth 900m. It is a constant depth 900m everywhere. When tide comes it start changing from 900m to 100m and even less. I specified in my Boundary condition file HBOR as 900, but for some reason it changes with movement of tide, it is decreasing. And as a result the velocities are too high. How can I secure the min water depth as 900m in spite of tidal activities? I probably made wrong changes in BORD3D as I am still learning fortran, could you please put me into right direction. So looks like tidal data is working but depth is affected dramaticaly. I use a tank model at the moment, before I apply real bathymetry. But I placed my tank in relevant geographical location to be able to extract the harmonic constant. Thanks a mil.

Kind Regards!

Violet