How to visualize air circulation between rooms?
The best way to see air flow is to use a fog there are commercial cans really expensive or if your grocery store has dry ice buy a pound, when you get home , put some warm water in a pan and put a chunk of the dry ice in the water, as the heat breaks the dry ice down a cloud of non toxic smoke that will leave no residue is released.
I used to put a couple bowls of water on the porch and in a fish pond (no fish) on Halloween, as long as there was no breeze the fog looked really cool and the kids loved it , we needed to check ventilation on some process benches and I used some pvc pipe water and dry ice to make the smoke in a clean room and check flow , putting the dry ice in a pan with warm water will do the same and makes it easy to see how the air is moving.