# Pitching moment at the quarter chord in CFX

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 April 22, 2011, 13:44 Pitching moment at the quarter chord in CFX #1 Member   Kisorthman Vimalakanthan Join Date: Apr 2011 Posts: 32 Rep Power: 7 Could someone please tell me how to calculate pitching moment at the quarter-cord location of an airfoil in CFX, as in the CCL expression? I have been using this equation, Cm = torque_y()@Airfoil/(Q*c) Q and c are the dynamic head and chord respectively. This equation seems to give a very different value to my comparison, this is may be due to the fact in CFX the force and the moments are defined at the global coordinate origin, in my case this is the leading edge of the airfoil. Any help is greatly appreciated, Thank you. mortazavi likes this. __________________ Kisorthman Vimalakanthan Dept. of Power and Propulsion Cranfield University Email: k.vimalakanthan@gmail.com

 April 24, 2011, 13:59 #2 Senior Member   Stuart Join Date: Jul 2009 Location: Portsmouth, England Posts: 484 Rep Power: 15 I think you are missing a reference area in your expression e.g. wing planform area (see http://en.wikipedia.org/wiki/Pitching_moment). Last edited by siw; April 24, 2011 at 14:23. Reason: Typo.

 July 15, 2011, 23:25 #3 New Member   Josh Yen Join Date: Jul 2011 Posts: 14 Rep Power: 7 Hi k.vimalakanthan, I was having the same problem as you and the CEL I used to find the moment was: moment = torque_y_Axis Name()@Airfoil Axis Name is the axis that you want the pitching moment to be calculated, in your case, an axis at the quarter chord location. To find the pitching moment coefficient, as siw said, you need to include the reference area so: CM = moment/(Q*S*c) Hope that helps

 April 8, 2016, 09:28 constant pitching moment #4 Member   alex Join Date: Feb 2016 Location: chennai Posts: 47 Rep Power: 2 hello all so pitching moment is calculated about y axis what is the location of y axis with respect to x and z

 April 9, 2016, 19:02 #5 Member   Join Date: Jun 2009 Posts: 50 Rep Power: 9 Hi all, this is my question too. Any suggestion for CL and CD and also the location of centre of pressure? many many thanks

 April 10, 2016, 06:38 centre of pressure #6 Member   alex Join Date: Feb 2016 Location: chennai Posts: 47 Rep Power: 2 hello mortazavi, u can create a local coordinate in cfx post and using function u can estimate moment about local coordinate. where ever u want.

 Tags cfx, moment, pitching

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