[FLASH-USERS] using viscosity in FLASH unsplit hydro

[Philip Chang]

Hi unsplit experts,

I have implemented a prescription for viscosity appropriate for disk (an 
alpha-like prescription) in FLASH 4 and using the unsplit hydro solver.  
However, it does not appear to calculate the appropriate courant time 
for the viscous terms.

The way the Config file is implemented is

REQUIRES physics/Hydro/HydroMain
REQUIRES physics/Gravity/GravityMain/Poisson/Multipole
REQUIRES physics/materialProperties/Viscosity/ViscosityMain/MyVisc

Do I also require something along the lines of
REQUIRES physics/Diffuse/DiffuseMain

to include the Diffuse_computeDt.F90 file to compute the proper viscous 
timescale or is this somehow done in Hydro_computeDt.F90 in the unsplit 
solver?  This part is confusing for me because it appears that viscosity 
is dealt with in an entirely different manner in the unsplit hydro 
solver compared to the split hydro solver.

Thanks.

Cheers,
Phil