open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear All,

I met a problem regarding tracer conservative issure.

This work is to study the flushing characteristic/ water retention times in an area. So I release tracer in the interesting area at a certain moment. Then I track the average tracer concentration in that area, which looks fine (As the black line). But the total mass of tracer is decreasing(Grean line).



I have check the previous posts,

and I have followed all the instructions for the consevative of tracer.

NUMBER OF TRACERS = 1
COEFFICIENT FOR DIFFUSION OF TRACERS = 1
OPTION FOR THE DIFFUSION OF TRACERS = 1
TREATMENT OF NEGATIVE DEPTHS = 2
OPTION FOR THE TREATMENT OF TIDAL FLATS=1
SOLVER FOR DIFFUSION OF TRACERS = 7
MASS-LUMPING ON VELOCITY = 1
TYPE OF ADVECTION = 1;5;14
MATRIX STORAGE = 3
TREATMENT OF FLUXES AT THE BOUNDARIES = 2

But I will don't understand why this happened and how to correct it?



Any advice will be appreciated.

Best Regards,
Bin

Hello Bin,

are you sure that you want a coefficient for diffusion of tracers equal to 1 ?
However, as a first step, I suggest you to do a simulation without tracer diffusion (set coefficient for diffusion of tracer = 0.d0).
Then, when you check the mass conservation, it is better to look to the relative error (see the listing), rather than the total tracer mass.

Hope this helps,

Best regards

Sara

Dear Sara,

Many thanks for your reply.

I have tested the model sensiivity to coefficient for diffusion of tracer, it has no big difference.
Model without tracer diffusion still experiences loss of tracer mass.

I think the loss of tracer mass is because the tracer pass through the open boundary.

Best Regards,
Bin