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Get inlet flow angle for computing lift and drag coefficients

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Old   October 30, 2015, 15:25
Default Get inlet flow angle for computing lift and drag coefficients
Join Date: May 2015
Posts: 98
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My problem should be simple: The lift of an airfoil is always in the direction normal to the free stream, and drag is in the opposite direction. I need a way of automatically getting the direction of the free stream velocity vector that is specified in myCase/0/U and read this into my system/controlDict file which computes the coefficients below:

myLiftDirection= (-sin(alpha) cos(alpha) 0 )
myDragDirection= (cos(alpha) sin(alpha) 0)

where alpha is obtained from the boundary condition file of the inlet velocity.

type forceCoeffs;
functionObjectLibs ("");
patches (fixedWall);
// pName p;
// UName U;
rhoName rhoInf;
rhoInf 1000;
CofR (0 0 0);
liftDir myLiftDirection;
dragDir myDragDirection;
pitchAxis (0 0 0);
magUInf 0.05; // Free stream velocity
lRef 0.3; // Diameter of cylinder?
Aref 0.0707; // Ref. Area = cross sectional area?
outputControl timeStep;
outputInterval 1;
Jack001 is offline   Reply With Quote


controldict, force coefficients, get values

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