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Hello,

I was trying to do mixed sediment transport modelling in my work. In my model, I have two classes of sediment, mud and sand. But I'm a little confused with some keywords related to mixed sediment.

1. The manual says the first class is non-cohesive and the second class is cohesive. But then it says the keyword COHESIVE SEDIMENTS = YES,NO. I tried this but it didn't work and the calculation crashed.
So I use COHESIVE SEDIMENTS = NO;YES and it works this time. But I'm not sure which class is mud and which one is sand in such case.

2.For the following keywords in the steering file, I give different values for each class(Here I assumed first class is sand and second class is mud):

INITIAL FRACTION FOR PARTICULAR SIZE CLASS = 0.3;0.7
SEDIMENT DIAMETERS = 0.001;0.0003
SEDIMENT DENSITY = 2650;1100

I'm not sure about the SEDIMENT DENSITY because in the dictionary it only has one default value. Should I give two values for mixed sediment?

Is there any other keyword which should be given two different values?
The steering file was attached below. Thanks in advance!

Hi
About the first point, I would say that the description of the keyword is OK. First class is non-cohesive (Sand) so value = NO. Second class is cohesive (Mud) so value = YES. It seems logical that your first trial (COHESIVE SEDIMENTS = YES,NO) doesn't work and the second trail works.
For the second point, you assumption is OK. the first value is for sand and the second for mud.
I'm not sure about Sediment Density.

Hope this helps

Thanks Christophe!
I will continue trying these keywords.

Hello,

To complete Christophe's answer, the sediment density is constant, but you need to specify the mud concentration in the bed layers, using the same keywords than for mud only.
'MUD CONCENTRATION PER LAYER, NUMBER OF LAYER FOR THE CONSOLIDATION MODEL, CRITICAL SHEAR STRESS'
you also need to initialize the bed layers using init-mixte.f...
- This part of the code is still underdevelopment, for example we don't take into account the consolidation for mixed sediments. The initialization will be made easier in the next version. -

Good luck !

Cath