I don't know if there's official terminology, but in Belanger's Vector menu it's called purge time and fill time, which allowed you to blow the chemical out onto the car and time the start of the next "fill" cycle so as the arms start moving as the chemical has just begun spraying.
You want to be careful not to add too much air. If you don't have bay
doors to block the wind, the chems have to be pretty wet or a breeze will just blow it away. It looks pretty good in your picture above, but I would have needed a much wetter application to get anything clean - there would have been much more on the ground.