Hello, I am wondering what will happen if I try to ventilate a room by natural ventilation through a single opening. In this opening there will be a ventilation grill. I already found a paper about counterflow through an open door by temperature differences: http://www.aivc.org/sites/default/files/airbase_4535.pdf But is this right for my problem? And how do I take the ventilation grill into account? Thanks in advance!