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

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-17-2015, 04:58 PM   #1 (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
I finally encountered The Force ( drag from a passing truck )

For years now I have read about you guys feeling the vacuum as a truck drives past you in the next lane.
I drive a '93 Civic hatch and have even had semi trucks pulling mobile homes, large busses, etc, and have never once encountered this phenomenon.

However, I just recently encountered what you guys are talking about on a trip to see my parents in Houston.
Speeds were 70-75 mph ( I'm just under that at 65-70 ) and a truck drives by me doing maybe 80-85.
As he goes by, I feel a sudden 'pop' in the air and heard myself saying out loud "whoa ! "

Here is what puzzles me - the truck was a 2012-2015 Ford F-150 lifted perhaps 6" with a grille bar on the front.

Why would I feel the phenomenon from a much smaller vehicle like this versus a semi ? Right place, right time, or is this something you guys encounter quite often ?

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-17-2015, 05:37 PM   #2 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,320
Thanks: 24,442
Thanked 7,387 Times in 4,784 Posts
vacuum

On the semi's,the trailer bottom is almost 4-ft off the road surface and this gap cannot support a transverse pressure gradient,as it just bleeds into the physical void.
The F-150 is lower,and side-to-side,does create a boundary in which the air is accelerated between the two of your vehicles.
You experience the Bernoulli effect,as the static pressure is converted to a partial vacuum by the displacement.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/
  Reply With Quote
The Following 4 Users Say Thank You to aerohead For This Useful Post:
BamZipPow (01-17-2015), Cd (01-17-2015), freebeard (01-18-2015), razordave (01-18-2015)
Old 01-17-2015, 09:25 PM   #3 (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
It was almost erie !
  Reply With Quote
Old 01-19-2015, 01:39 AM   #4 (permalink)
Not bad for a machine
 
dirtydave's Avatar
 
Join Date: Mar 2014
Location: Baltimore
Posts: 1,024

Maechunbu - Retired - '00 Kia Sephia 1.8I4 16VDOHC
Last 3: 45.28 mpg (US)

Slasher - '96 Chevy Corsica 2.2L 3speedauto
Duct Tape Aero Crew
Team Chevy
90 day: 34.76 mpg (US)
Thanks: 279
Thanked 242 Times in 179 Posts
I have felt it driving a 26' international box truck. Getting passed or passing someone else the sideskirts do make a difference. I have seen a lot more lately
__________________




  Reply With Quote
Old 01-25-2015, 12:15 PM   #5 (permalink)
EcoModding Lurker
 
Join Date: Jan 2015
Location: toronto
Posts: 8
Thanks: 0
Thanked 40 Times in 2 Posts
this happens to me often.
  Reply With Quote
Old 01-25-2015, 12:36 PM   #6 (permalink)
Master EcoModder
 
cowmeat's Avatar
 
Join Date: Jan 2014
Location: South Carolina
Posts: 1,659

Princess Carriage - '20 Ford Explorer Limited

Silver - '22 Ford Maverick Hybrid XLT w/tow pkg
Maverick Hybrids
90 day: 41.3 mpg (US)
Thanks: 128
Thanked 764 Times in 461 Posts
Here's my experience with it:

http://ecomodder.com/forum/showthrea...tml#post464933

http://ecomodder.com/forum/showthrea...tml#post464949
__________________

  Reply With Quote
Old 01-26-2015, 04:02 PM   #7 (permalink)
Beating EPA Unmodded
 
Join Date: Oct 2014
Location: Oklahoma City
Posts: 143

Blue Eagle - '10 Honda Civic LX
Team Honda
90 day: 31.12 mpg (US)
Thanks: 4
Thanked 29 Times in 23 Posts
I feel this force occasionally. I pulled up behind a semi today that was going 75 and my MPG went up to 50. I was really far behind the truck too. I've also had the gauge read 150 going 60ish when I was behind a truck. Trucks pass me all the time here in Oklahoma, and I feel this force quite a bit. It's not really something I notice too often, since whenever I am getting passed by a truck I feel like it is throwing me off to the side of the road

__________________

  Reply With Quote
Reply  Post New Thread






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