I've seen several references to a "bubble effect" that apparently happens on the leading face of a vehicle where a recessed feature can cause air to build up in front of it, hindering airflow. Examples would be:
-Recessed grille openings
-Recessed fog light bezels
-Recessed headlights
Generally, it seems, placing a smooth sheet over these features will streamline airflow. If I am headed in the wrong direction, please point me straight!
My question is this: How "flush" behind a grille does a grille block need to be for maximum effectiveness?
My Cruze Eco has an upper grille that's mostly blocked. It has a hexagonal grille pattern that is blocked, leaving the pattern exposed at the front. The center section of the grille has the same hexagonal pattern, but the holes go through. See this pic:
Chevrolet Cruze Eco 2011 2011 Chevrolet Cruze Eco - Grille View
If I was to design a variable shutter grille block, the simplest thing I could do would be to build a box structure behind the grille with shutters in the back of the box. This, however, would leave a large air "pocket" between the grille and the shutters when the shutters are closed.
Would it be worth the extra effort to build something that sat closer to the grille to minimise the amount of air between the grille and shutters?