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

forces: What are magUInf, lRef, Aref?

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

Reply
 
LinkBack Thread Tools Display Modes
Old   March 6, 2011, 16:07
Default forces: What are magUInf, lRef, Aref?
  #1
Member
 
Klaus
Join Date: Mar 2009
Posts: 70
Rep Power: 8
klausb is on a distinguished road
Hello,

I want to optimise a wing, hence analyse cl/cd using the forces function but I don't know the meaning of some variables (magUInf, lRef, Aref).

Actually my wing is a hydrofoil therefore the high rhoInf = 1000 kg/m3 for water.

Her the "draft" entries in my controlDict:

functions
(
forces
{
type forces;
functionObjectLibs ("libforces.so"); //Lib to load
patches (stlSurface); // change to your patch name
rhoInf 1000; //Reference density for fluid
rhoName rhoInf;
CofR (0.15 0 0); //Origin for moment calculations
outputControl outputTime;
}
forceCoeffs
{
type forceCoeffs;
functionObjectLibs ("libforces.so");
patches (stlSurface); //change to your patch name
rhoInf 1000;
rhoName rhoInf;
CofR (0 0 0);
liftDir (0 1 0);
dragDir (1 0 0);
pitchAxis (0 0 0);
magUInf 55.5; //?
lRef 0.6; //?
Aref 1; //?
outputControl outputTime;
}

What are magUInf, lRef, Aref?

Klaus
klausb is offline   Reply With Quote

Old   March 6, 2011, 16:58
Default
  #2
New Member
 
GregorS's Avatar
 
Gregor Seljak
Join Date: Oct 2010
Posts: 21
Rep Power: 6
GregorS is on a distinguished road
Hi!

a.) magUInf is relative velocity between hydrofoil and water.
b.) lRef is length of hydrofoil, which is equal to chord length of hydrofoil profile.
c.) Aref is area of your hydrofoil, which is chord length*span. If you are doing 2D simulation, then span is equal to z coordinate.
GregorS 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
Forces in V1.6 terrybarnaby OpenFOAM 71 July 8, 2014 10:42
forces on a hydrofoil vaina74 OpenFOAM Running, Solving & CFD 5 March 30, 2010 07:30
Forces calulated through pressure LVDH OpenFOAM Post-Processing 2 February 26, 2010 04:15
Convergence moving mesh lr103476 OpenFOAM Running, Solving & CFD 30 November 19, 2007 15:09
Valve Forces in CFdesign Mike Clapp Main CFD Forum 3 March 8, 2001 15:09


All times are GMT -4. The time now is 00:46.