scalar convergence

CFD-Student

I'm modeling atmospheric flow over a cubic obstacle with h2 dispersion (buoyancy on) behind the building. I'm runing a transient case. I'm having trouble fixing my model to correct the following messeges:

*** WARNING #009 ***THE VALUE OF SCALAR SC1 IN CELL 36 ( -6.7978-320) IS BELOW THE MINIMUM ( 0.0000E+00)

SCALAR VALUES BELOW THE ACCEPTALE MINIMUM FOUND AT *** CELLS •(after 100 time steps)

*** WARNING #013 *** MAXIMUM SPECIFIED CORRECTOR STAGES 20 REACHED BEFORE CONVERGENCE CRITERION IS SATISFIED.

-SCALAR EQUATION 1 NOT CONVERGE-

I suppose these are related. I have read all messeges that I could find on this problem... still not really clear on what to do.

For the scalar equation I'm using the CD (BF=1) 150 sweeps and 0.01 residual tolerance

Performed a grid check (tetrahedral) and the only prblems are a few angles (face) below limit

Avg Courant No. between 10-1

any suggestions?

THANKS A LOT!

Hector