# turbine force_y vs dP * area

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 May 3, 2019, 00:02 turbine force_y vs dP * area #1 Senior Member   Svetlana Tkachenko Join Date: Oct 2013 Location: Australia, Sydney Posts: 407 Rep Power: 14 In ansys 19.2 the built in function force_y()@turbine Default and a similar manual calculation (here 'top' and 'bottom' are circular surfaces below and above the turbine) (areaAve(Pressure)@bottom - areaAve(Pressure)@top ) * area()@top give different results 2-3 times, inconsistently in different cases as it is not a linear relationship. Is this a known issue? How do I troubleshoot this? Can attach a small test case if anyone is interested.

 May 3, 2019, 02:26 #2 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,694 Rep Power: 143 your areaAve functions just average the pressure over the surface, they do not take into account direction. The force_y function only gets the force in the y direction. So your function is not working out the force in the y direction. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 May 3, 2019, 02:31 #3 Senior Member   Svetlana Tkachenko Join Date: Oct 2013 Location: Australia, Sydney Posts: 407 Rep Power: 14 In this case my calculations should give larger values than CFX's force_y, because they do not multiply by cos (direction angle) in each point. However in my case the "dP * area" calculation gives results which are 0.3 to 0.7 of the force_y value predicted by CFX.

 May 3, 2019, 02:34 #4 Super Moderator   Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,694 Rep Power: 143 If you want us to help you, you are going to have to post an image of what you are analysing, a description of what the top and bottom surfaces are and a plot of the pressure distribution. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

 Tags lift and drag, post procesing, propeller, turbine