this is what i'd like to know. been searching, but haven't found any definate answers. found THIS paper. it is for flow around a wheel only (not in wheel arch). although not 100% clear from visualisation, it does seem to have a low pressure zone in front of wheel, and a high pressure zone on top of wheel. would be handy to get the paper it references, as this has models of a wheel in a wheel arch. SAE wants $$ for it though. also read something about vents on top of wheel arches being to vent pressure when suspension is compressing. not too sure about this.
Wow interesting link and in complete contradiction to what I've read about wheels and aerodynamics. From what I have read (and I can't remember the book name now, dammit) open wheel aerodynamics are very much the opposite to the findings of that link (and intuitively I also would have thought different) and that the front of a free wheel was a high pressure zone, slowing a car down and wose still, creating a 'pool' of high pressure air at the bottom front of the wheel, pushing upwards (bad). According to the book, where ever possible it was highly advantageous (if the race series regs allowed it) to put a cowl or arch over an open wheel which better deflects air over it and avoids build up in this front bottom pocket. As an example, see rear F1 wheels and how the underbody diffuser turns upwards just in front of them. Not saying the info in that paper is wrong (seems to be modelled correctly from what I can see.... it's a pretty simple system), it just seems to contradict what I had read which was based on both anectdotal evidence and I believe wind tunnel testing. Ben
