open atmosphere condition
 

i'm trying to calculate the interference of two air cooled heat exchangers.
those are setted in open field, so i made a cubic as a flow field.
bottom of this flow field i put little holes for velocity inlet. about 7 m/s.
and i setted all other walls as pressure outlet. and gave a k-e std turbulence condition.

the cubicle is 87x90x30(meters)
velocity inlet is 7 m/s
the size of inlet holes are 4x9(m) and 5x9(m) in the bottom.

the problem is,
i ran the calculation, but it was not converged.
in the residual plot, continuity is almost just flat.

1. how do i converge the continuity?
2. what conditions do i choose in turbulence velocity inlet?
there are 4 options, right?
-K and epsilon
-intensity and length scale
-intensity and viscosity ratio
-intensity and hydraulic diameter
which one do i want? i still don't figure out which one used when.
i choose intensity and lenth scale. (can't tell exactly why)

do i clear enough for what i want to know?

sorry for my english and please give me some advise.
thank you