to prepare a Scenario using define Input, we have an Option with the
Name of "Dispersion", and here is " Additional
vertical Diffusion", I selected the "Use results from
hydrodynamics" and "Scale factor" is 1 but model is not
converged but for a low scale factor like 1e-006 it is converged. I
read the Manual of Delwaq and it was said that this factor is to
Change the Units of D-FLOW results in such a way to correspond the
Delwaq calculations. However, using IM (inorganic Matterial) it Needs
settling velocity as m/d (meter per day) and D-FLOW results are SI, it
means the Dispersion unit is m2s-1, velocity ms-1, ... Does
Delwaq convert the D-FLOW automatically in m/d or grm-3 (in
comparison with kgm-3) or we should apply the Scale factor by
Dispersion? To make the Problem undestandable, what means a scale
factor for additional vertical Diffusion of 1e-007?
Why for such scale factor Delwaq converges but for higher
values, e.g. 1, it does not converge?
When I need a scale factor?
Does scale factor only chanage the Additional vertical Diffusion,
which was calculated already through D-FLOW turbulence model (k-Epsilon)?
Why for small scale factors the model convergs?
There is some misunderstanding here. The scale factor for the
vertical dispersion/diffusion is really a scale factor for that
parameter only. In the "raw" input you can use scale factors
in several locations to facilitate conversion from one unit (the one
you find in reports for istance) to another (the one used by the
DELWAQ calculation itself). That is what the documentation is
referring to or should refer to.
The flow field is read as is and the proper units are m3/s for the
flow, m2 for the area and m3 for the volume.
The problem you are facing wrt the stability/convergence has to do
with the iteration parameters. The GUI puts in default values, but
sometimes you need different ones - try increasing the threshold
Tolerance to 1.0e-5 and the maximum number of iterations MaxIter to
1000. This may help the calculation to reach a converged state.