[mjans]

Hi,
im using swak to calculate the velocity in cylindar coordinates in runtime for further calculations.
Therefor I compared the swak-calculated values with the results using convertToCylindrical and realised, that on patches having an mixingplane as boundary condition these values are not the same .

I'm running the simulation with foam-ext 3.1 using swak4Foam-0.3.1.

Checking the values with ParaView 4.4 in the field showed, that the swak-values are everywhere conform to the ones calculated by convertToCylindrical except the ones on the mixingPlane patches.
(faceSets e.g. are ok (check faceSet INLETZONE_OUTLET_face e.g.)

Finally I wanted to check if the used cartesian velocity values cause the problem. Therefore I simply did no transformation (expression "U";) which produced swak-values identical to the common "U" values, even on the mixingPlane patches.

To calculate cylindrical velocity, I used the following function:

functions (
compute_VCyl
{
type expressionField;
fieldName VCyl;
dimension [0 1 -1 0 0 0 0];
variables (
"xVariable= pos().x;"
"yVariable= pos().y;"
"Polarwinkel= 0;"
"Polarwinkel=(xVariable>0)?atan(yVariable/xVariable):Polarwinkel;"
"Polarwinkel=(yVariable>=0&&xVariable<0)?pi+atan(y Variable/xVariable):Polarwinkel;"
"Polarwinkel=(yVariable<0&&xVariable<0)?-pi+atan(yVariable/xVariable):Polarwinkel;"
"Polarwinkel=(yVariable>0&&xVariable==0)?pi/2:Polarwinkel;"
"Polarwinkel=(yVariable<0&&xVariable==0)?-pi/2:Polarwinkel;"
"A= tensor(cos(Polarwinkel),sin(Polarwinkel),0,-sin(Polarwinkel),cos(Polarwinkel),0,0,0,1);"
);
expression "A&U";
autowrite true;
outputControl timeStep;
outputInterval 1;
}
);

libs ( "libOpenFoamTurbo.so" "libswakFunctionObjects.so" );

This is part of the controlDict in the small testcase "cylindrical", which shows the Problem. You can download it from

https://github.com/mjans/swak_mixingplane.git

There is also the case "cylindrical_ggi" where all mixingPlanes are replaced by ggi and the case "cylindrical_notrafo" writing the velocity U to V using the mentioned swak-function.

If anyone knows something about that or can help me with this, I'd be very happy.

Thanks
Marian