What turbulence scale to use for "still" air?

Chris

I am modeling a racecar wing (w/ endplate) for my undergraduate senior design project. An additional goal is to become proficient with Fluent as I have never used CFD software before this semester.

I have run a few solutions now, both times using the k-epsilon (realizable) turbulence model. I am using intensity and scale for the BC's, 1% turbulence intensity (because I read that <1% is appropriate for the still-air situation). Since the wing is moving through what I am assuming to be undisturbed air, what is the proper scale to use to define the eddies? I have used .25m and .5m so far. (The wing has a .75m half-span-length and is in a 3mx3mx5m volume but I am probably going to increase that volume). And since the k-e model was chosen with rather little knowledge, is that a good choice? It is moving at 70 m/s and I'm also using the pressure-based solver. Any other suggestions to improve the learning process? I have found the Fluent documentation to be extremely informative.

Thanks for any advice! Chris Newport