smoke sim origin clearance between collision object?

In order for the smoke simulation to work a collision object has to be one unit away from the flow object otherwise smoke is not emitted??
To explain what I am saying I create a flow object then scale it down .125 and put a open ended cylinder around it and scale the cylinder down .5 then run the simulation, but no smoke is emitted.
If increase the size of the cylinder so that there is one unit of clearance all is well and smoke is emitted.
Anybody else notice this or is it possible to emit smoke from circumstances such as these, where there is less than one unit of clearance between the flow object and collision object?

this is quite puzzling.
anybody else have a clear explanation?

Actually I also had rund some tests and found out that you need to bump up the resolution of the domain quite a bit in this case. Do you have a .blender ready?

I adjusted the domain and I think that is working for what I need.
thank you.