CFD Online Discussion Forums - [swak4Foam] and atan2

I found a solution to the problem. I used a sequence of ifs written down as ternary operators. The math is taken from here:
https://de.mathworks.com/matlabcentr...from-0-to-2-pi

This is the snippet to use in funkySetFieldsDict. Please note, I'm in the y-z-plane instead of the x-y-plane used in the explanation. I simply replaced x by z. Please check if the angle definition fits your coordinate system before use.

Code:

myVariables (

    // code for y-z-plane polar angle

    "theta=0;"



    //if x>0

    //    v=atan(y/x);

    //end

    "theta=(pos().z>0)?atan(pos().y/pos().z):theta;"



    //if y>=0 & x<0

    //    v=pi+atan(y/x);

    //end

    "theta=((pos().y>=0)&&(pos().z<0))?pi+atan(pos().y/pos().z):theta;"



    //if y<0 & x<0

    //    v=-pi+atan(y/x);

    //end

    "theta=((pos().y<0)&&(pos().z<0))?-pi+atan(pos().y/pos().z):theta;"



    //if y>0 & x==0

    //    v=pi/2;

    //end

    "theta=((pos().y>0)&&(pos().z==0))?pi/2:theta;"



    //if y<0 & x==0

    //    v=-pi/2;

    //end

    "theta=((pos().y<0)&&(pos().z==0))?-pi/2:theta;"



    //if v<0

    //    v=v+2*pi;

    //end

    // uncomment if you need the angle range to be 0:2pi instead of -pi:pi

    //"theta=(theta<0)?theta+2*pi:theta;"

);

Best regards, Luk