Quote:
Originally Posted by sendler
He's talking about the mirror which has a cut out in the step to allow the pathway for vision.
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This mirror is an example of what I am talking about regarding a concave area to set up the swirl. Even though Morelli doesn't specify a concave form, I think we would agree his research on this concept is incomplete. I would intuitively suggest that a concave form with a knife edged break leading to a quarter round inner wall/ base joint feature would be the most efficient shape in order to set up the rolling toroidal air formation needed for the root of the fluid tail. With a concave depth approaching half the narrow width of the outer oval.
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The inner round over might not make much difference but the concave depression seams obvious to me. I would love to see some comparative coast down data on the Prius with the concave truncated tail that was posted above. Even though it followed the body and was not perfectly oval, it looks like it would be very effective even though the swirl would not approach the ideal toroid motion because of the corners.
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Okay,thanks!
Yes,the clear plastic portion is a box-cavity,which is capturing a locked-vortex,which the outer flow skips over like Morelli's fluid tail.
The length,and inset dimension of the cavity respect the ideal pathway.The 'cut-out' is just a practical consideration.
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The Prius extension is a box cavity as well,with a transverse separation line which gets equal pressure basically all around which is better for a higher base pressure and overall lower drag.
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It does lack Morelli's requirement for the transom geometry necessary for the fluid tail.If you look at the Fiat Punto mods,the roof extension appears to be softening the edge radii between the attachment point and trailing edge,rolling it and morphing into a more elliptical cross section.I did this with the CRX best I could.
