CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > Main CFD Forum

How to calculate the vehicle front/rear lift forces

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   May 17, 2013, 05:03
Default How to calculate the vehicle front/rear lift forces
  #1
New Member
 
Fayong.zhang
Join Date: Nov 2012
Posts: 2
Rep Power: 0
zhang6425532 is on a distinguished road
How to calculate the vehicle front/rear lift force? I know how to calculate the whole car lift force, but how to calculate the front/rear lift force separately?
zhang6425532 is offline   Reply With Quote

Old   May 17, 2013, 06:30
Default
  #2
Senior Member
 
Lefteris
Join Date: Oct 2011
Location: UK, Greece
Posts: 187
Rep Power: 5
Aeronautics El. K. is on a distinguished road
Which software are you using?
__________________
Lefteris

Aeronautics El. K. is offline   Reply With Quote

Old   May 17, 2013, 10:15
Default
  #3
New Member
 
Fayong.zhang
Join Date: Nov 2012
Posts: 2
Rep Power: 0
zhang6425532 is on a distinguished road
Quote:
Originally Posted by Aeronautics El. K. View Post
Which software are you using?

Star-ccm+ and fluent both ok
zhang6425532 is offline   Reply With Quote

Old   May 19, 2013, 08:19
Default
  #4
Member
 
Gajendra Gulgulia
Join Date: Apr 2013
Location: India
Posts: 86
Rep Power: 4
ggulgulia is on a distinguished road
Hey Zhang

I am not giving you a software custom method to calculate the vehicle lift. What I am about to mention in the foregoing discussion is a standard method for calculating the lift/drag forces at any region of the body

The region of interest has to be explicitly defined in the code. For lift coefficient calculation you need to have the area (Vector) of the region normal to the longitudinal direction of the vehicle, say A, and the density of the fluid flowing over the surface of the vehicle, say d, The force has to be calculated by the expression in the code you will be using (all of the softwares nowadays have an inbuilt expression to calculate the force on the surface of interest. This force, say F, is fund out by running the simulation. Then you can create a custom expression to get the force coefficient and running the same in iteration. The following formula has to be used for calculating the force coefficient:

C= F/(0.5*d*A)

For drag coefficient F is along the direction opposite to the fluid flow or along the direction of the area vector, and for lift coefficient F is along the direction aligned with the vertical of the local coordinate system
ggulgulia is offline   Reply With Quote

Old   May 19, 2013, 08:21
Default
  #5
Member
 
Gajendra Gulgulia
Join Date: Apr 2013
Location: India
Posts: 86
Rep Power: 4
ggulgulia is on a distinguished road
.. and yeah if you are using STAR CCM+ , you can get the example in one of the tutorials given in the help file of the package

PS sorry for the long reply posted previously.. it's just that I emphasize a lot in keeping the basics clear
ggulgulia is offline   Reply With Quote

Old   May 19, 2013, 13:23
Default
  #6
Senior Member
 
Join Date: Mar 2009
Location: Austin, TX
Posts: 134
Rep Power: 9
kyle is on a distinguished road
You can get the aerodynamic lift, drag and moment from your CFD software and then do some very simple static analysis to determine the aerodynamic load on each axle.
kyle is offline   Reply With Quote

Old   May 19, 2013, 13:50
Default
  #7
Senior Member
 
Lefteris
Join Date: Oct 2011
Location: UK, Greece
Posts: 187
Rep Power: 5
Aeronautics El. K. is on a distinguished road
Quote:
Originally Posted by zhang6425532 View Post
Star-ccm+ and fluent both ok
I think that in Fluent you can choose the surface that you want and have it calculate the aerodynamic forces on these surfaces. I'm not so sure about that though.


Quote:
Originally Posted by ggulgulia View Post
... and for lift coefficient F is along the direction aligned with the vertical of the local coordinate system
Lift is in the direction perpendicular to the flow direction.
__________________
Lefteris

Aeronautics El. K. is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Lattice Boltzmann, LIFT and DRAG forces Puigar Main CFD Forum 0 October 15, 2012 08:57
using forces for geting drag and lift force magnitude? 510_ Main CFD Forum 2 October 28, 2010 11:42
how to calculate forces on the wall with free surface? phsieh2005 Main CFD Forum 2 July 13, 2010 08:11
Trying to calculate lift and drag forces vkrastev OpenFOAM 0 January 27, 2010 12:33
Calculate forces without hydrostatic pressure geir_oye FLUENT 4 November 12, 2009 10:12


All times are GMT -4. The time now is 14:16.