09-17-2013, 01:17 PM
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#71 (permalink)
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kach22i -- Six posts between [Yesterday, 05:43 PM] and [Yesterday, 06:25 PM]. You're a machine.
I like the '32 Ford front suspension w/ leading arm torsion bars and centered steering box. I wonder what that front tire size is though.
I'll be looking at the Roger Wood story to find out what is said about 'passive porosity'. The underbody diagams in #68 and cfd_guy's #69 are helpful.
cfd_guy -- A is fixed by the vehicles purpose. Cd is a unitless number.
Last edited by freebeard; 09-17-2013 at 01:24 PM..
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09-17-2013, 03:42 PM
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#72 (permalink)
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Quote:
Originally Posted by freebeard
cfd_guy -- A is fixed by the vehicles purpose. Cd is a unitless number.
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Yes I know but CdA is a better number to use to associate to fuel mileage from the force or drag.
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09-17-2013, 07:02 PM
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#73 (permalink)
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As for the Volvo link : only the C30 Drive / coupe version got the belly panels, not the rest of the range.
From personal experience, I doubt very much the - awfully heavy - aerodynamic wheels ever helped its mileage much.
The Hyundai underside shot is bogus, showing the flow to be nicely lengthwise underneath.
It gets pushed out sideways.
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Strayed to the Dark Diesel Side
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09-18-2013, 01:21 AM
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#74 (permalink)
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Quote:
Originally Posted by myself
I'll be looking at the Roger Wood story to find out what is said about 'passive porosity'.
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Interesting article. Some observations: - Reynolds number is important in interpreting wind tunnel results and explains why little stick-on tabs won't affect the air around a larger vehicle.
- Roll- up door instead of swing door equals free box cavity.
- "The sides and top of a trailer do not generate pressure drag, not even in crosswinds."
As for passive porosity, I found:
Quote:
Originally Posted by Google
[PDF] SIMULATION OF FLOWS WITH PASSIVE POROSITY - ICAS is
http://www.icas.org/ICAS_ARCHIVE/ICA...102.PDF
by NT Frink - 2002 - Cited by 2 - Related articles
ICAS 2002 CONGRESS. 2102.1. SIMULATION OF FLOWS WITH PASSIVE POROSITY ... International Council of the Aeronautical Sciences, with permission
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I hope they don't mind my sharing this:
It's pretty exciting. My panel van will have a full PolyMetal bellypan and a boattail made from Goodwill trampolines.
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09-19-2013, 02:21 AM
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#76 (permalink)
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This one did it for me. I'm not buying the flow over the hood.
OTOH confirmation bias allows me to totally accept the passive porosity thing.
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09-19-2013, 12:17 PM
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#77 (permalink)
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Quote:
Originally Posted by freebeard
This one did it for me. I'm not buying the flow over the hood.
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It's looks quite normal to me.
This one below puzzles me to no end.
Rocket Car Design Project
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09-20-2013, 02:33 AM
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#78 (permalink)
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Quote:
It's looks quite normal to me.
This one below puzzles me to no end.
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It looks to me like there's a series of progressively larger bug deflectors on the hood. Doesn't the high pressure bubble at the base of the windshield have air circulating through it instead of being a locked vortex?
The one 'below' shows the area that is in magenta here.
This is why the bubble top vanagon has better air flow than the pop-top.
Check the numbers.
I wish I could find pictures of Beetles racing in the rain. There's a water roostertail about 6 feet high off the windshield.
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09-24-2013, 08:54 AM
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#79 (permalink)
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1939 Maybach Stromlinienkarosserie:
This shows that air flows up from under the car and it flows around to the top, behind the rear wheels. And this would be addressed by having a narrower rear wheel track.
The Schlörwagen has a similar issue, though the solution there might be to widen the tail into a "beaver tail":
Last edited by NeilBlanchard; 09-24-2013 at 09:14 AM..
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