open TELEMAC-MASCARET The mathematically superior suite of solvers

Hi!

I am currently about to set up a model for aquaculture in a lake. What I would like to do is to estimate the spreading of solid material (fish pellets and fish fecals) on the bottom of the bed. To identify the deposited material from the initial bed material, I guess I somehow should define the initial bed thickness to 0, or set an non-erodible bedover my whole lake.

I guess the smartest way to include the sediment as a source is simply through SEDIMENT = YES, and a tracer called SEDIMENT? Is it possible to define two different sediment sources (for the different sediment characteristics of pellets and fecals)?

Any suggestions from the skilled modellers out here? Thanks in advance!

/schmirre

Hello Schmirre,

As I see it, you do not need to set erodible bed thickness to zero, unless you want to eliminate any other sediment transport except fish pellets and fecals. That of course would make things simpler since you would only have to deal with two 'sediment' classes in your domain (fish pellets and fish fecals). You can define settling velocities for each one. I suppose sediment stratification would be important (enable it with keyword ACTIVE LAYER THICKNESS in SISYPHE).

Setting erodible bed thickness to zero everywhere is a piece of cake. Just replace in noerod.fwith
You then need to define the sediment sources within the water column, which is something I never dealt with, so maybe another member can provide more insight.

Best Regards,
Costas

Thank you Costas, that was straight forward and working perfectly fine.

To ensure that my results only show the deposition of the source material, I also choose to set EROSION COEFFICIENT = 0, and this seems to work well for my application. For my purpose, I only need to model the extent of the sediment plume, and therefore I thought it wise not to pay too much attention to the sediment stratification.

I am now modelling sediment sources in T3D simply using SEDIMENT = YES and a tracer 'SEDIMENT'. As I am modelling two different sediments, are there a way of representing both of these, with different characteristics in one run?

I am not familiar with T3D but I know that it includes a built-in model for modeling sediment transport (SEDI-3D), which you can set up within T3D cas file. I have never used it and cannot help you with that.

On the other hand, you can couple T3D with SISYPHE, where you can define up to, I believe, 10 sediment classes. So, with SISYPHE you can model both.

Costas

I see. Well I found good "documentation" in the fortran files of SEDI-3D.

I am aware that sispyhe enables definition of multiple sediment classes, but I guess I would have to define sources that are not on the boundary in the same manner as in SEDI-3D?

/schmirre