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substance file for sediments

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costas matsoukis, modified 5 Years ago.

substance file for sediments

Youngling Posts: 2 Join Date: 7/23/13 Recent Posts
Hello,

I am trying to set up a very simple model for sediments with only sedimentation and erosion on.
When making the substance file, although it is quite clear for sedimentation I am not very sure about erosion.
What parameters do I have to tick in process Transport S1-S2 so that I can get in the editable process parameters of GUI the critical shear stress for erosion and the zeroth order resuspension flux?
I am asking because I see that in the available default file for sediments these parameters are activated but when I am trying to make my own I cannot get them.
And also, why in Transport S1-S2 the total resuspension flux DM from layer S is available twice? what is the difference?

Thank you in advance,

Costas
Christophe Thiange, modified 5 Years ago.

RE: substance file for sediments

Jedi Knight Posts: 125 Join Date: 11/15/12 Recent Posts
Hi Costas,

What parameters do I have to tick in process Transport S1-S2 so that I can get in the editable process parameters of GUI the critical shear stress for erosion and the zeroth order resuspension flux?

After selecting the substances (IM1, IMS1 and maybe IMS2) you should activate process Sed_IM1 (sedimentation of IM1). In the configuration of this process you can make Tau editable or choose to have it computed by process 'CalTau'.

why in Transport S1-S2 the total resuspension flux DM from layer S is available twice? what is the difference?

This is a minor bug in the GUI that cuts of the description strings. So the first one is actually: 'total resuspension flux DM from layer S1' and the second one: 'total resuspension flux DM from layer S2'

The value of these fluxes can be imposed or computed by process Res_DM. If you go for Res_DM, you will find the zeroth order resuspension flux as one of its input parameters.

Hope this helps.
HR
Huub Rijper, modified 2 Years ago.

RE: substance file for sediments

Youngling Posts: 2 Join Date: 4/5/17 Recent Posts
Hi Christophe,

It has been a while since this thread was posted. But I have the exact same answer as Costas, but you answer on the question about the critical shear stress for erosion does not the issue for me.

I also have to model some very basic sedimentation and erosion with three substances IM1, IM2 and IM3. The like Costas it is easy to find where adapt the critical shear stress for sedimentation, but the "critical shear stress for resuspention" cannot be found, strangely enough. I suspect it to be somewhere in the configuration for "Resuspention, transport in S1-S2 IM".

So the define my question: how can I turn on the "critical shear stress for resuspension", which is defined in N/m2? Should I maybe turn on a different setting before I can turn on this setting?

Thank you in advance,

Huub
Michel Jeuken, modified 2 Years ago.

RE: substance file for sediments

Jedi Knight Posts: 156 Join Date: 1/21/13 Recent Posts
Hi,

With resuspension you need an extra process to be switched on to calculate the total mass of sediment material that resuspends into the water column using the Res_DM process. Based on the actual composition of the sediment layer, the fractions of IM1/2/3 are used to determine how much of each is actually resuspended. The "critical shear stress for resuspension" is part of that extra process. After selecting it as the input for 'total resuspension flux DM, you can find it when pressing the extra process button on the main screen, and go to the Res_DM process
HR
Huub Rijper, modified 2 Years ago.

RE: substance file for sediments

Youngling Posts: 2 Join Date: 4/5/17 Recent Posts
Thank you very much Michel! This has resolved my problem. Many thanks!

Huub
GS
Gholamreza Shiravani, modified 4 Months ago.

RE: substance file for sediments

Padawan Posts: 53 Join Date: 6/25/16 Recent Posts

Dear Michelle,

I read the Manual but I did not understand that activating  IM1S1 is to calculate the resuspension of already defined IM1 in S1 or is the resuspension of sedimented IM1 during the Simulation? If the latter is right, why we are not able to define the critical shear stress of Erosion for IM1 and we can only define one critical shear stress of resuspension (Erosion) for S1!, while the critical shear stress for Erosion of IM1,IM2 and IM3 are different and also different from S1?

What means the Zres (Zero order resuspension rate)? How it will be estimated or calculated?

 

I would be happy on your answers.