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June 19, 2012, 12:08 |
Moment coefficient on moving mesh
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#1 |
Senior Member
Join Date: Apr 2010
Posts: 151
Rep Power: 16 |
Quick question: I use forces to calculates forces and moments on a moving object. The forces are well calculated, but the moment is not, and I think this is because the center of rotation (CofR) is fixed in system/controlDict:
Code:
functions { forces { type forces; functionObjectLibs ( "libforces.so" ); outputControl timeStep; outputInterval 1; patches (foil); pName p; UName U; rhoName rhoInf; log true; rhoInf 1000; CofR (0 0 0); liftDir (0 1 0); dragDir (1 0 0); pitchAxis (0 0 1); magUInf 0.4; lRef 0.1; Aref 0.002; } |
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June 19, 2012, 17:15 |
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#2 |
Senior Member
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I don't have much of experience on this but if you know where your CofR is in time, then you can easily evaluate the moment around any other point P:
Mp1 = Mp2 + p2p1 x F Where: Mp1 = moment around point p1 Mp2 = moment around point p2 p2p1 = vector going from p2 to p1 F = the force which generates the moment x = cross product |
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June 20, 2012, 01:33 |
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#3 |
Senior Member
Join Date: Apr 2010
Posts: 151
Rep Power: 16 |
Brilliant!
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October 28, 2015, 11:31 |
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#4 |
Senior Member
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Tags |
cofr, forces, moving mesh |
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