Air Flow thru rads

[ian.stewart]

Im having a discussion elsewhere about heat transfer and coolant speeds, and a few questions have raised their head that im not sure about, Its a long time since I have worked with fluid dynamics, that is if what I remember about fluid dynamics is relevant??
1, There has to be a speed where the flow of water thru the rad is to fast to allow good heat transfer to the air, or is it benificial to slow the water thru the rad by restriction to aid cooling??
2, Do fans, electrical or mechanical, pushers and pullers, help with cooling at speeds above say 10mph, which for arguments sake is the fans max speed of air flow??
3, What percentage of airflow that hits a typical ally rad actually passes thru the rad compared with airspeed of the car, and I assume is it possible to reach a point of max airflow that a rad will flow.
Ian