View Single Post
Old 04-16-2011, 04:28 PM   #130 (permalink)
aerohead
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 16,363
Thanks: 24,463
Thanked 7,400 Times in 4,794 Posts
force

Quote:
Originally Posted by winkosmosis View Post
Exactly. The airflow is applying a force to the bubble in the tube, just like airflow applies a force to the front of the vehicle and the windshield bubble.
*The vehicle is attacking the air mass in front of it and this onset flow is impinging upon the air captured within the pitot and connecting tubing to create the dynamic head.
* While it is true that the the onset flow creates the stagnation pressure at nose and windscreen,it is the pressure differential between the forward stagnation point,and the base pressure of the wake which creates the 'force' the vehicle must overcome.
* The bubble ( which is barely distinguishable over the windshield) can be thought of as a solid structure as far as the air is concerned.
---------------------------------------------------------------------------
* With respect to the 1999 GM PNGV Precept,the 'features-drag' which included wipers,wheel covers,mirrors,door handles,and cut lines added a total 0.007 to the Cd.The wiper drag was zero.
  Reply With Quote