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hi everybody,

I have 2 open boundaries in my t3d simulation: River and sea
and 3 open boundaries in my gaia simulation river (inflow suspended CO) and sea east (inflow bedload NCO), and sea-west (outflow bedload and suspended CO+NCO).
I applyed Prescribed concentration of tracers in t3d steering file, got results of 2 boundaries for suspended and bedload. without sediment movements.
After that I applyed sediment concentrations in gaia steering files. got results of 2 boundaries for suspended and bedload. with sediment movements.

is it possible to simulate with this configuration : 3 open boundaries in Ga and 2 in T3d? How?

thx for the help,
Josias

Hi Josias,

I think it is not possible to have different numbers of open boundaries for t3d and gaia. Besides, I think physically it makes sense that it is not possible.

To find a good solution it would be helpful to understand why you split your open boundary at the seaside for the sediments.

Even if there is only 1 open sea boundary, each boundary node can be treated seperately. You can give a non-equal distribution of sediments at the open boundary. I guess that could be one solution. It can be done by fortran routines or if it is not so complicated also by the boundary file (you can give explicitly the concentration per bounday node in column 9 -- see 2.1.2 in gaia user manual).

Furthermore all boundary conditions for suspended sediments need to be described in the gaia steering file. In case you use prescribed concentration of tracers in t3d I guess gaia uses the default value of prescribed suspended sediments concentration values (which is 0) which would explain the missing sediment movements.

Best regards,
Rebekka

hi everybody,
hi rebekha,
following your advice, I kept 2 boundaries for Gaia and T3d assigning the desired concentration in the boundary condition file.

when running a simmulation after adapting the cohesive Lock exchange example all is good I think,
cohesive inflow at the boundary number 2,
when I use the Non-Cohesive gaia case file, adapting both steering files t3d and ga, there is this error.





I want to have the NCO, flowrate at boundr. 1 , and CO at boundr 2.

thx for the help

Josias

Hi Josias,

I don't understand what you mean be NCO, flowrate at boundary 1 and CO at boundary 2. You have only one sediment class which is non-cohesive. So there can not be a boundary condition for a cohesive sediment.

Your error message is a typical one if you have zero water depth at the inflow boundary. First check your initial water levels. Telemac can not start from zero water level. If you can simulate at least one time step you can check your boundary conditions (are the velocities at the boundaries in the correct direction, is their magnitude useful)

Best regards,
Rebekka

Hi Rebekha,


following what you said I did run a simulation with 1 cohesive and 1 non cohesive declared, with the same configuation as previous one: the same error.
I changed then the INITIAL CONDITIONS from tpxo to 1 m, I got only one time step computation and the same error message.

I checked the results files, comparing those ones to my previous t3d simulation, without coupling, at the same period. what I found :
- water level evolution are pretty similar :
from 1 to 1.34 for t3d-ga (with error) and (slightly growing faster)
from 1.07 to 1.3 for t3d only

- currents for the t3d-ga tend to be at least 10+ time stronger/faster than for t3d.

t3d




t3dgaia



note: as I have multiple results files (multiple color scales) for the failing simulation, i tried to show you a single zone with a 'unic' color scale.

thx for the help

Hi everybody, hi Rebekha.

Solved! I think, I need few more tests to be sure. But seems good even heavy computation. Any advices to make my gaia computation lighter???!!!

Thx for your help

Josias