[aleisia]

I applied OUTFLOW BC at a trailer's inlet, and the trailer purifies the contaminanted air and supply pure air through windpipes (velocity inlet BC.) into offices.

About Outflow BC at the trailer's inlet. I read fluent help file, and I know that outflow can correct the mass balance of the domain and has no impact on upstream flow, but in my model, the outflow should be balancing the velocity inlet BC through the windpipes in the offices. But clearly I have some contaminant in the air, and at the inlet of trailer, but I set it as pure air at the inlet of windpipes in the offices. So what about the species conservation? Does the "correct mass balance" mean that outflow BC only takes care of the air mass balance between trailer inlet and windpipe inlet so that the trailer doesn't "inhale" any contaminant into it? Or do I have to set a surface source sink at the inlet to represent the "sucking" of contaminant?

Thanks!