open TELEMAC-MASCARET The mathematically superior suite of solvers

Dear Sisyphe's Users,

I am coupling the telemac2d with sisyphe to model the transport of both non-cohesive and cohesive (i.e. bed material's size classes = 2) in an estuary. The hydrodynamic process has been validated, so the calculated bed shear stress was correct with the max. value of 13.44 N/m2 in a narrow channel during an ebb tide (e.g. h = 8.24 m, uv = 2.08 m/s)

The output of sediment particulate analysis as in Figure 1, and model setting for sisyphe as bellow:

INITIAL SUSPENSION CONCENTRATIONS = 0.00E00;1.74E-6
INITIAL FRACTION FOR PARTICULAR SIZE CLASS = 0.82;0.12
SEDIMENT DIAMETERS = 1.20E-4;1.00E-5 (m)
D90 = 2.50E-4;6.00E-5 (m)
SETTLING VELOCITIES = 6.45E-4;1.00E-5 (m/s)
CRITICAL SHEAR VELOCITY FOR MUD DEPOSITION = 1.10E-2 (m/s)
PARTHENIADES CONSTANT = 6.00E-5 (kg/m2/s)
CRITICAL EROSION SHEAR STRESS OF THE MUD = 0.150;...n10=0.150 (N/m2)
MUD CONCENTRATION PER LAYER = 1325.;...n10=1325. (kg/m3)

For validation purposes, I am comparing the modelled with the observed turbidity, by linearly converting it from the suspended sediment concentration (SSC), (i.e. non-cohesive + cohesive). Refer Figure 2.

As the difference of modelled compared to the observed turbidity is over 1log10 lower, I have increased the initial cohesive concentration from 1.74E-6 to 4.36E-5. This however caused the concentration of cohesive decreased with time while at less than 100 mg/L. Refer Figure 3.

Questions:
1. Is there any general range for relationship between turbidity and SSC?
2. What is the explanation behind the decreased of cohesive concentration while at the higher value?
3. Which parameter is the most sensitive to calibrate the cohesive in suspension, (i.e. refer to my case)?
4. What is the difference between SEDIMENT DIAMETERS and MEAN DIAMETER OF THE SEDIMENT, as I only used the default value .01;...n10=.01 for the later?

Thank you, Amyrhul