open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello!

I want to run a cohesive sediment case by coupling Telemac2D with Sisyphe. When I defined the keywords：

NUMBER OF LAYERS OF THE CONSOLIDATION MODEL = 1
MUD CONCENTRATION PER LAYER =500
CRITICAL EROSION SHEAR STRESS OF THE MUD =0.50

There will be errors in the calculation results of the hydrodynamic module.Especially in the first time step, the velocity is very high, which will lead to a great erosion of the bottom bed at the beginning: TITAL MINIMAL EVOLUTION = -99.99.

But when I assign a value greater than 1 to the keyword "NUMBER OF LAYERS OF THE CONSOLIDATION MODEL"(also changed the CONCENTRATION and EROSION SHEAR STRESS)，the hydrodynamic results will back to normal.Does anyone know the cause of the problem?

Besides,after reading the user manual, I still confused about the meaning of the keyword "MUD CONCENTRATION PER LAYER" and how to set the appropriate value.

Thankful for any help!

Gareth