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Dear Users,

I wonder if any one can help me with my problem on prescribing the tracers values at source. Currently I have stratification with two layers in my domain: bottom layer Temp at +4.34C and Salinity at 35; and the top layer Temp at +1C and Salinity at 25. All this entered in CONDIM subroutine.

Now I am trying to add the source at the bottom of the domain with different constant tracers parameters as Temperature -0.28C and Salinity 0. I have already specified the Values of tracers at the source in Steering file with velocity and water discharge as well, but the tracers at the source are not picked up in the run, only discharge and velocity is considered. I added subroutine T3D_TRSCE to fortran file as well but I am not really sure how to modify it as I thought that the values of tracers should be picked from steering file and I cannot find any validation cases with similar subroutine to take it as an example.

My goal is to see how stratification is effected by adding various, than in domain, tracers values at discharge. I have attached cas and fortran files. I hope somebody could point me into right direction.

Thanks.

Kind Regards!

Violeta

Hello Violeta,

It should work, the values of tracers at the sources in the steering file must be given in the following order : values of all sources for tracer 1, values of all sources for tracer 2, etc., so that it fills array TASCE that will be used as TASCE(I,ITRAC) where I is the source rank and ITRAC the tracer rank (there is some confusion in documentation regarding this order). You can check in t3d_trsce if it is called and what values of TASCE(I,ITRAC) are taken. Then the values are copied into a block TA_SCE that is sent to CVDF3D where advection-diffusion of tracers is done.
One thing to understand is that the correct quantity of tracer is entered into the domain with the correct value, but the computed value of the tracer at the source may not be what you give, because the tracer discharge is diluted in the volume around the point (so it is not a Dirichlet condition). So what should tell you if the tracer gets into the domain is the mass-balance indicating what fluxes have been received.

I hope this helps, regards,

Jean-Michel Hervouet

Hello Jean-Michel,

Thank you very much for your reply. I was trying to amend the t3d_trsce subroutine yesterday but was not successful. I run similar case before without including this subroutine and values of tracers at sources very picked from steering file but it does not work now. The difference with my current case is that I added stratification to it and after that the value of tracers at source is not working anymore. Other parameters as discharge, velocities etc of source are working but not the tracers. Even it is diluted in domain but when I do cross section I still can see the vertical plume when I look at velocities, turbulent energy etc. parameters but when I look at tracers then the plume does not exist. In my previous simpler case it worked.
I looked at sortie file at mass balance info and there is a discharge on Water section, in Tracer 1 and Tracer 2 sections it is not so clear as info is given at boundaries or source together and I already have one open boundary. I still do not understand how to read the Tracers info properly so easily could miss the errors displayed there, but for some experienced eyes it could be very obvious what I have done wrong.
So I thought to add t3d_trsce subroutine even I do not have the source file and I see there is a part on TASCE to be taken from the steering file and that what I need, but I am not sure what do I have to enter in this subroutine as values already are specified in cas file. Also the system confusion could be due to forcing having on bottom layers (from 0 to 600m up) the tracers: Temp 4.3 and Salinity 35 that is already specified in CONDIM subroutine. My source is nearly at the bottom (2m) and tracers values are different: Temp -0.28 and Salinity 0. I just do not know how to overwrite it as looks like system ignores the tracers value at the source but pics other parameters ok. Sorry for long post. Please let me know if you need more info about my case. I attached the output and other files, just in case. Thanks a mil.

Kind Regards!

Violeta

Hello Violeta,

Well if I look at your listing, at the first time step it says :

mass leaving the domain : -50 (this would be 50 entering : the source with a discharge of 50 and a time-step of 1 s).

then the mass of tracer 1 exiting the domain is said to be 14, this is 50 * -0.28, it is said exiting but in fact it is -14 entering. Tracer 2 has no flux entering because the tracer value is 0.

So for me it seems that all is OK, except that I do not see the flux through an open boundary that you mention but if you start from still water, there is probably no velocity on this boundary at the first time step, so this would be normal.

For me your source is thus duly taken into account. In your listing we see that tracer 1 has an increase of mass of 700 over the run, which is correct (but certainly hardly visible since the initial mass is 0.28...E+13).

With best regards,

Jean-Michel Hervouet

Thank you so much Jean-Michel. It is much clear to me now and gives me some confidence in correctness of my files. I will run the case for much longer period and see what happens to the stratification.

Yes, you are right, I have no velocities at the boundaries yet, the main goal is to check the plume and discharge and then I will add more activities to the case:).

Thanks a mil for your prompt reply.

Kind Regards!

Violeta