# Calculation of Cf in Openfoam

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

 January 21, 2014, 23:46 Calculation of Cf in Openfoam #1 New Member   rajesh Join Date: Jun 2012 Location: Bangalore Posts: 9 Rep Power: 5 Dear all, I am doing simulation of flow past Selig airfoil.. I am wondering how to calculate co-efficient of friction?? if anybody knows. Pls respond.

 January 22, 2014, 13:05 #2 Member   Eric R Join Date: Jul 2012 Posts: 83 Rep Power: 5 Use the "wallShearStress" utility and find the resultant of the three components that are output for you. This gives you . Divide that by freestream dynamic pressure and you get Cf.

 January 23, 2014, 06:35 #3 New Member   rajesh Join Date: Jun 2012 Location: Bangalore Posts: 9 Rep Power: 5 Dear Eric Thanks for your reply. I calculated resultant of the three components as V = sqrt(u_sq+v_sq+w_sq). Is this the way to calculate resultant of 3 components? By this i get only positive values. If there is separation in the flow, i should get negative Cf.

 January 23, 2014, 08:56 #4 Member   Eric R Join Date: Jul 2012 Posts: 83 Rep Power: 5 That is correct. Since your flow has separation, there will be a local minimum value of Cf accompanied by an increase. I'm other words, your graph will approach zero Cf but will begin to diverge away from it. You must locate this value and manually place a negative sign next to the values in your region after separation.

 January 27, 2014, 05:09 #5 New Member   rajesh Join Date: Jun 2012 Location: Bangalore Posts: 9 Rep Power: 5 Dear Eric, Thanks a lot

 Thread Tools Display Modes Linear Mode

 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 OffTrackbacks are On Pingbacks are On Refbacks are On Forum Rules

 Similar Threads Thread Thread Starter Forum Replies Last Post rawe666 OpenFOAM Running, Solving & CFD 12 December 3, 2015 16:21 wyldckat OpenFOAM Bugs 18 October 21, 2010 05:51 chiven OpenFOAM Running, Solving & CFD 4 September 14, 2009 04:44 Valle OpenFOAM Running, Solving & CFD 4 August 19, 2009 05:53 oseen OpenFOAM Installation 9 August 26, 2007 13:50

All times are GMT -4. The time now is 18:28.