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- - Swirled inlet (https://www.cfd-online.com/Forums/openfoam-solving/162659-swirled-inlet.html)

Hi everyone,

I have some cases with straight, coaxial pipes where I would like to have swirl at the inlet.
In the incompressible/simpleFoam tutorials I found this inlet condition, that is supposed to create swirl.

Code:

    type            codedFixedValue;

        redirectType    swirl;



        code

        #{

            const vector axis(0, 0, 1.5);



            vectorField v(2.0*this->patch().Cf() ^ axis);

            v.replace(vector::Z, -1);

            operator==(v);

        #};

        value           $internalField;

I used this code and it works quite fine for me. I have a magnitude velocity of 1 m/s as wished.

Only the swirl is strange. Instead 1.5 m/s the absolute velocity maximal is only 0.0115 m/s.

I would like to understand the definition of the 1.5 m/s which are obviously not 1.5 m/s.

Best
Gerrit

Hi,

By try and error, I found it my self.

Code:

 {

    type            codedFixedValue;

        redirectType    swirl;



        code

        #{

            const vector axis(0, 0, 1);            // Axis of rotation



            vectorField v = 20.0*this->patch().Cf() ^ axis;    // Angular velocity in rad/s

            v.replace(vector::Z, -1);                                    // Velocity of mainflow

            operator==(v);

        #};

        value           $internalField;

     }

Thank you Gerrit for sharing what you figured out.