open TELEMAC-MASCARET The mathematically superior suite of solvers

Good morning, I went to simulate the spread of a tracer from a side dish liquid with constant imposed on the boundary of the computational domain. In the representation of the result to get the tracer values all equal to zero. I report an interaction of the simulation:


ITERATION 90 TIME: 1 MN 30.0000 S ( 90.0000 S)

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ADVECTION STEP

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DIFFUSION-PROPAGATION STEP
EQUNOR (BIEF) : 52 ITERATIONS, RELATIVE PRECISION: 0.9671216E-09

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DIFFUSION OF TRACERS STEP
GRACJG (BIEF) : SOLUTION X=0 BECAUSE L2-NORM OF B VERY SMALL: 0.000000

BALANCE OF TRAC 1 (UNIT: )

QUANTITY OF TRACER: 0.000000
BOUNDARY 1 FLUX: 0.000000 ( >0 : ENTERING <0 : EXITING )

ABSOLUTE ERROR: 0.000000

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BALANCE OF WATER VOLUME
VOLUME IN THE DOMAIN : 0.1998161E+10 M3
FLUX BOUNDARY 1: 0.1223562 M3/S ( >0 : ENTERING <0 : EXITING )
RELATIVE ERROR IN VOLUME AT T = 90.00 S : -0.2178538E-15
PRERES: MAXIMUM COURANT NUMBER: 0.8924562E-01



Can anyone tell me why I did not take into cinsiderazione the tracer diffusion?
I hope for your help

regards

Luca

Hello,

You should check your boundary conditions file, on lines where you have water entering, starting with 4 5 5, you should have also a 5 further on the line, to impose the tracer, whereas sometimes users wrongly let a 2 that means solid boundaries. I suppose that you have given PRESCRIBED VALUES OF TRACERS for every liquid boundary. If you have given only one value, it may apply to the wrong boundary.

Seeing your steering file would thus be also useful, and you seem to be in primitive equations, and wave equation would be faster.

Regards,

JMH

Thank you so much, if I understand I have to do having a boundary liquid composed of three nodes, each node must add a tracer with an initial value. If I run the simulation get that value from each concentration is always equal in time, that does not undergo change.

Below I attach my files steering.

What should I do to add so that the value of the tracer in various time?

I hope for your help

regards

Luca

Hello,

Well I do not see any real mistake in the steering file, so difficult to say where is the problem without the liquid boundaries file and the boundary conditions file. You can however improve the steering file :

Remove the line : STEERING FILE= ...

Choose TYPE OF ADVECTION : 1;5;5 if no tidal flats
or TYPE OF ADVECTION : 1;5;14 with tidal flats

Add :

TREATMENT OF THE LINEAR SYSTEM : 2
SOLVER : 1
MASS-LUMPING OF H : 1.
MASS-LUMPING OF VELOCITY : 1.
FREE SURFACE GRADIENT COMPATIBILITY : 0.9

Without LIQUID BOUNDARIES FILE, you should see initial tracers set at the value of 1, without entering values of 100, this could be also checked.

Regards,

JMH