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Dear all,
Greetings!

I have doubts regarding the salinity study. I gave given the salinity data to the model using a separate file in .txt format. the model was running but the results did seem not fine. I need to know if there are any other methods to do the study? like giving the input in any other methods????

waiting for the reply.

thanks and regards

sidharth kr

Hello Sidharth kr,

Can you clarify what you have exactly done please? What did you do by "given the salinity data to the model using a separate file in .txt format.". Was it a file given as initial condition and interpolated at every node? Or did you force salinity at some locations and at every time step (or at a few time steps)?

A classical way to model salinity in TELEMAC-3D is to use a density law taking into account salinity (see keyword DENSITY LAW in the TELEMAC-3D user manual) and initial conditions for salinity (in the steering file, reading it in another file or programming it thanks to Fortran files, e.g. USER_CONDI3D_TRAC subroutine).

Hope this helps,

Chi-Tuan

Dear Pham,

thanks for the reply. I have given the file for every time step to do the modeling. I will attach the files. I have done the simulation by considering the density law to account. but the problem is the result seems not fine. I have the doubt that whether we can do the same for temperature too ??

thanks and regards
Sidharth

Hello Sidharth,

So, you have given salinity and temperature as input data with the liquid boundaries file.
What do you mean by results not fine. Can you upload figures for results + what you expect please?

Looking at your steering file, I have a few comments:
- you should increase NUMBER OF HORIZONTAL LEVELS. With 2, you only have 2 planes corresponding to the bottom and the free surface. You will not get any stratification e.g. (in that case, using another MESH TRANSFORMATION can help if you try to model such phenomenon),
- you should use the default choice NON-HYDROSTATIC VERSION = YES when dealing with active tracers/scalars like salinity and/or temperature (see e.g. the TELEMAC-3D validation manual for the lock exchange example),
- you should read the recommendations of the TELEMAC-3D user manual (appendix E),
- before coupling with sediment module, you should solve your issue, step by step,
- I would advise you to try k-epsilon model for both horizontal directions (choice 3) or mixing length turbulence model over the vertical (VERTICAL TURBULENCE MODEL = 2) rather than Smagorinski over the vertical (VERTICAL TURBULENCE MODEL = 4),
- you may have to refine your mesh if it is too coarse.

Hope this helps,

Chi-Tuan

thank you, Pham. I will make these changes and will share the results.
hope your comments help a lot!

thanks again for your valuable reply.

Dear Pham,

as you said the changes were made and the results came and it seems well. I have another doubt, is there any other way to do the salinity/temperature study other than giving in the liquid boundary file?
is there any way that I can give the spacially varying salinity and temperature data in an SLF file? or any other way.

thanks and regards.

sidharth

Dear Pham,

I am updating my question, I have the doubt that is it possible to give a file given as the initial condition and interpolated at every node for the salinity and temperature?
if yes what file can be used. I need spacially distributed salinity/temperature which also varies in time also.

thanks and regards
Sidharth kr

Hello siddharthkr111,

Reading the TELEMAC-3D user manual and in particular the beginning of chapter 7 "Tracert transport", you could imagine 2 ways to do what I have the feeling to understand:
- implementing the reading of the initial values of temperature and salinity defined at every node of the 3D mesh in USER_CONDI3D_TRAC as they are not simple constant values. You can use e.g. BINARY DATA FILE 1,
- run a computation from a PREVIOUS COMPUTATION FILE with option COMPUTATION CONTINUED = YES in which you have previously stored the 3D mesh with z elevation, 3D velocity components + temperature + salinity (less effort of implementation, but you have to generate the PREVIOUS COMPUTATION FILE).

For the boundary conditions, if you need complex boundary conditions (e.g. conditions varying along the vertical), you can implement what you want in USER_BORD3D or BORD3D subroutines.

Hope this helps,

Chi-Tuan

Dear Pham,

I tried the second option that you mentioned in the discussion. but I didn't achieve what I need.

I have salinity and temperature for the domain. and I interpolated the salinity and temperature with the mesh. I want to do the simulation using this interpolated mesh and want to see the changes with time.is there any way to do so? or what is the procedure to interpolate the data at every time step for every node? I have the data only for a particular time.

also can you please explain the first method that you have mentioned?

thanks and regards
Sidharth kr