Quote:
Originally Posted by kach22i
An important goal indeed, but in this situation he (the original poster) wanted the flow to stay attached. Maybe his goals should be re-examined.
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You misunderstood me I think. I am saying that attached flow will always be required for the ideal aerodynamic car, but, It is a consequence of good design, it is not the main goal. Everyone gets all hairbrained about attached flow like that is the only thing we need to accomplish in order to achieve aerodynamic nirvana, but it is not. Of course he wants attached flow, he probably has it now, but just because the flow is attached does not mean it is optimized. You need to carefully consider how fast the air is being asked to close in behind the shape, if it is too fast, it creates low pressure. If this low pressure is in close proximity to an area of high pressure, the air will move up from the high to the low and if strong enough a difference, will set a vortex in motion which will be a real drag.
And Yes, If you have something sticking up on a car, a mini template is the best way to mitigate the damage done. I always look at AC units on RV roofs and think "That should be mini-templated". But, when you look at the major structures of cars, like the trailing edge of the roof, you can't just start with a mini-template there and expect it to be optimal, it probably wouldn't hurt, but it won't minimize the drag for the space that it takes up.
Again, I'm not saying here that the existing Kamm is a disaster, just that it is not optimal. It is giving back 60-70% of the potential gain for a structure of it's size and type when it could be doing 100%