[NotOverUnderated]

Hi,

I am running a sliding mesh simulation (fixed region + rotating cellZone) and I would like to use forceCoeffs function object to compute the lift and drag coefficients for some airfoils that are located in the rotating cellZone.

I have a question about the vectors liftDir and dragDir: Are they specified in a fixed frame of reference or they are relative to the cellZone on which the airfoil is located? in other words, does OpenFOAM automatically take care of rotating these two vectors (liftDir and dragDir) accordingly when the cellZone (in which the airfoil is located) is rotating?

I appreciate your help.

Best regards

[NotOverUnderated]

I've found that OpenFOAM v7 does this automatically* (when it computes the lift and drag it actually uses the tangential and the normal forces but this is not the case for OpenFOAM v6 or OpenFOAM v2006.

I don't know how this feature was introduced in OpenFOAM v7 without any details (I can't find anything about it) or even how to disable that to restore the old behaviour (similar to OF6, etc.).


* I've compared the output of forces & forceCoeffs function objects of both OF6 and OF7 and I've parsed the contents manually using a python script to make this conclusion.

Could someone please explain or give a link to explain when OF7 implemented this feature?

Thanks

[jeast]

I am having the same issue, but specifically with moment calculations from the forces function object. What is the best way to report forces and moments on a patch that moves (and rotates) as part of a cellZone? Has anyone else experienced this issue?