# How to get the distance from an unknown point and an axis?

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 July 21, 2015, 05:55 How to get the distance from an unknown point and an axis? #1 New Member   Felix Join Date: Apr 2015 Location: GER Posts: 9 Rep Power: 11 Hi there. Im pretty new here but just read much the last couples of months, now I have a prob. I have a domain with a blade of a Windturbine. I want to calculate the torque which is the result of the force at the bladesurface and the distance to the pitch axis. For the distance (actually the moment arm), I need the point where the integral pressure stresses the blade, so how can I get this point to use it in an expression? If I could find this anywhere in the Forum, you guys maybe give me a hint and apologize. Thanks!

 July 21, 2015, 06:24 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,703 Rep Power: 143 Have a look at the equations which define centre of pressure. CFX has a wide range of integration functions in the CEL, so you should be able to adapt the CEL to the equation you require.

 July 22, 2015, 10:18 #3 New Member   Felix Join Date: Apr 2015 Location: GER Posts: 9 Rep Power: 11 Alright, thanks mate, I think I'll find a solution, maybe I tried it to complicated and just have to use the torque functions in the right way.

 July 22, 2015, 12:04 #4 Senior Member   Edmund Singer P.E. Join Date: Aug 2010 Location: Minneapolis, MN Posts: 511 Rep Power: 20 Yes, why are you doing it that way? Put a coord system at the point of blade rotation and get the torques around it.

 July 23, 2015, 09:21 #5 New Member   Felix Join Date: Apr 2015 Location: GER Posts: 9 Rep Power: 11 Got it, sorry :/ ... aaaaand: THX!

 Tags axis, distance calculator, integral pressure, point