Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 03-29-2012, 08:26 AM   #1 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,373
Thanked 2,172 Times in 1,469 Posts
More drag reduction studies

Searching for the author of the paper Vekke posted on drag reduction for the A2, hoping to find more on the rear box fairings, I found a separate paper that expanded the reporting of the "box cavity" findings seen in the paper Vekke posted: "Base Pressure Recovery using Rear Cavity and Base Plates".

And for future reference, in case the longer list of papers paulu found are taken down, here is the "table of contents" for the site:

Session 0-1 - Mike Dickison, Programme Manager Coventry University LCVTP
An Introduction to the Low Carbon Vehicle Technology Programme.

Session 0-2 - Peter White, Professor of ThermofluidDynamics Coventry University, Chairman Automobile Division IMechE
Reducing carbon emissions does aerodynamics matter?

Session 0-3 - Chris Johnson, director, design project work coventry university
Aesthetics and aerodynamics

Session 0-4 - Trevor Haynes, Coventry University
LCVTP Workstream 12: Aerodynamics Technical Introduction

Session 0-5 - Trevor Haynes, Coventry University
Aerodynamics and Electric Vehicles

Session 1-1 - Scott Porteous, Development & Simulation Ricardo UK Ltd
LCVTP Workstream 12 - Aerodynamics Efficiency - Sensitivity Analysis of aerodynamic drag over various drive cycles

Session 1-2 - Gianluca Orso Fiet, MIRA
LCVTP Aerodynamics Process Development

Session 1-3 - Rishi Gupta, Mechanical and Automotive Engineering Dept. Coventry University
LCVTP WS 12 Aerodynamics Support Activities at Coventry University

Session 2-1 - Remus Cîrstea, Coventry University
Effect of rear body taper on a simple body

Session 2-2 - Jeff Howell, Tata Motors European Technical Centre
WS12 Aerodynamic Performance University Research Projects Base Pressure Recovery

Session 2-3 - Nick Sabrazat, MIRA
LCVTP Aerodynamics Reference car finding:Lessons learned

Session 2-4 - Adrian Gaylard, Technical Specialist Aerodynamics Jaguar Land Rover
Base Pressure Recovery using Rear Cavity and Base Plates

Session 3-1 - Jeff Howell, Tata Motors European Technical Centre
WS12 Aerodynamic Performance University Research Projects Wheel/Wheelarch Drag

Session 3-2 - Adrian Gaylard, Technical Specialist, Aerodynamics, Jaguar Land Rover Drag Reduction Through Wheel Design

Session 3-3 - Nick Sabrazat, MIRA
Wheel Arch Flow Investigation

Session 4-1 - Hussain Ali, Tata Motors European Technical Centre
Drag reduction on a production vehicle

Session 4-2 - David Plummer, Design Institute Coventry University
Aesthetic Design

Session 4-3 - Adrian Gaylard, Technical Specialist, Aerodynamics, Jaguar Land Rover

Further Opportunities
Posters
Posters 1
Posters 2

__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.




Last edited by California98Civic; 03-31-2012 at 04:16 PM..
  Reply With Quote
The Following 9 Users Say Thank You to California98Civic For This Useful Post:
aerohead (03-31-2012), AndrzejM (03-30-2012), Cd (04-04-2013), jime57 (03-29-2012), landsailor (03-30-2012), MobilOne (08-23-2016), PaleMelanesian (03-30-2012), Rokeby (03-29-2012), Sven7 (03-29-2012)
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 03-29-2012, 11:33 AM   #2 (permalink)
Master EcoModder
 
Join Date: Dec 2011
Location: Boise Idaho
Posts: 842
Thanks: 39
Thanked 89 Times in 69 Posts
http://wwwm.coventry.ac.uk/researchn...ple%20body.pdf

This article is IMPORTANT. I recommend you save it, read it, and learn it.

This article is saying you can reduce drag 40 percent by making a tail. And the tail does not have to be very long.

And according to them, 20 degrees is about the absolute max, and even at that you are going to have problems with the bottom, but it is still worth it.

This article is worth SAVING.
  Reply With Quote
The Following User Says Thank You to drmiller100 For This Useful Post:
ChazInMT (03-29-2012)
Old 03-29-2012, 09:55 PM   #3 (permalink)
Cyborg ECU
 
California98Civic's Avatar
 
Join Date: Mar 2011
Location: Coastal Southern California
Posts: 6,299

Black and Green - '98 Honda Civic DX Coupe
Team Honda
90 day: 66.42 mpg (US)

Black and Red - '00 Nashbar Custom built eBike
90 day: 3671.43 mpg (US)
Thanks: 2,373
Thanked 2,172 Times in 1,469 Posts
Quote:
Originally Posted by drmiller100 View Post
http://wwwm.coventry.ac.uk/researchn...ple%20body.pdf

This article is IMPORTANT. I recommend you save it, read it, and learn it.
Very interesting. Some of it looks like a section on tail end shapes in Hucho, but this has more images and discussion than what I recall. There are a few articles in that table of contents that should be of interest here.
__________________
See my car's mod & maintenance thread and my electric bicycle's thread for ongoing projects. I will rebuild Black and Green over decades as parts die, until it becomes a different car of roughly the same shape and color. My minimum fuel economy goal is 55 mpg while averaging posted speed limits. I generally top 60 mpg. See also my Honda manual transmission specs thread.



  Reply With Quote
Old 03-29-2012, 11:31 PM   #4 (permalink)
Master EcoModder
 
Join Date: Mar 2008
Location: USA
Posts: 568
Thanks: 1
Thanked 73 Times in 58 Posts
Did I read correctly in thinking that 80 degree taper = 80 degree angle from the vertical tail section, or 10 degree diversion from horizontal?
  Reply With Quote
Old 03-30-2012, 05:16 AM   #5 (permalink)
Master EcoModder
 
Join Date: Apr 2011
Location: Europe
Posts: 364

ZX - '97 Citroen ZX Monaco
OldContinents
90 day: 61.05 mpg (US)
Thanks: 8
Thanked 31 Times in 25 Posts
Quote:
Originally Posted by Otto View Post
Did I read correctly in thinking that 80 degree taper = 80 degree angle from the vertical tail section, or 10 degree diversion from horizontal?
I guess so, 90 degree would be level, so 80 degree would be 10 degree off from level position, that is how it seems to be when comparing pictures on that document as 70 degrees is much more steeper angle, meaning it is 20 degrees off from horizontal.

edit:
For 1.33m height, one after body would be 0.1064m long so two would be 0.2128m long, which would then need to be angled to 10 degrees angle downwards from trailing edge. That sounds horribly lot what I had in my car last summer and would explain my fuel economy gains a bit, even I did not have full height sides or bottom in there, also it means that there is lot more to be gained.
__________________


Last edited by jtbo; 03-30-2012 at 05:26 AM.. Reason: idea
  Reply With Quote
Old 03-30-2012, 10:26 AM   #6 (permalink)
Master EcoModder
 
Join Date: Dec 2011
Location: Boise Idaho
Posts: 842
Thanks: 39
Thanked 89 Times in 69 Posts
I read it as 80 degrees is 10, and 70 degrees is 20.

I also read it as 20 is probably fine for the top of the roof, and 20 works for the sides, but does not work for the bottom of the car unless ground clearance is "right".
  Reply With Quote
Old 03-30-2012, 05:44 PM   #7 (permalink)
Master EcoModder
 
Join Date: Oct 2008
Location: Mid-Atlantic
Posts: 491

OurInsight - '06 Honda Insight
Thanks: 170
Thanked 69 Times in 44 Posts
The base cavity and base plates kinda blew my mind. I don't think Hucho addressed either so that was a great surprise. It is also interesting that they claim large gains from such short cavity lengths.

I was also totally brown away by the base plates. I would have thought that there would have so much turbulance between the body and base plate that it would have been counterproductive. Definitely some new ideas here.

What you thinking Phil?
  Reply With Quote
Old 03-31-2012, 03:38 PM   #8 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 15,861
Thanks: 23,922
Thanked 7,207 Times in 4,640 Posts
Hucho

Quote:
Originally Posted by jimepting View Post
The base cavity and base plates kinda blew my mind. I don't think Hucho addressed either so that was a great surprise. It is also interesting that they claim large gains from such short cavity lengths.

I was also totally brown away by the base plates. I would have thought that there would have so much turbulance between the body and base plate that it would have been counterproductive. Definitely some new ideas here.

What you thinking Phil?
Hucho addresses this technology back in the commercial vehicle chapters.These plates are exactly what Continuum Dynamics developed at NASA Ames Research Center,Palo Alto,California decades ago.
I did one of these 'egg crate' boat tails behind my semi model and it flowed just fine.
By limiting where the air can be,and providing locked-vortices all around,the outer flow can skip over the egg crate as with Texas Tech's cab wing/half tonneau on the pickup.
They're not as good in a crosswind,but they're way out ahead of nothing,extremely light,easy to manufacture,and should cost very little.
  Reply With Quote
Old 03-31-2012, 05:54 PM   #9 (permalink)
Master EcoModder
 
euromodder's Avatar
 
Join Date: Jul 2010
Location: Belgium
Posts: 4,683

The SCUD - '15 Fiat Scudo L2
Thanks: 178
Thanked 652 Times in 516 Posts
Quote:
Originally Posted by aerohead View Post
By limiting where the air can be,and providing locked-vortices all around,the outer flow can skip over the egg crate as with Texas Tech's cab wing/half tonneau on the pickup.
The pick-up rear gate / partial bed cover seems a good analogue when trying to understand how these base plates work.

Quote:
They're not as good in a crosswind,but they're way out ahead of nothing,extremely light,easy to manufacture,and should cost very little.
And when disguised as a cargorack or bikerack, or actually doing double duty as a rack, it won't draw that much attention.
__________________
Strayed to the Dark Diesel Side

  Reply With Quote
Old 03-31-2012, 06:32 PM   #10 (permalink)
Cd
Ultimate Fail
 
Cd's Avatar
 
Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,585
Thanks: 2,872
Thanked 1,121 Times in 679 Posts
( Actually, to be fair it should be mentioned that Paulu made note of the studies posted here on page 2 of the original thread - but its good to have a dedicated thread on this. )

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com