CFD Online Discussion Forums - [swak4Foam] How to use funkySetFields for surface scalar 'phi'?

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How to use funkySetFields for surface scalar 'phi'?

Hi everyone,

I met a problem when using funkySetFields for surface scalar field 'phi'. Basically I want to non-dimensionalise my case through dividing the fields by its reference values. I used the code below for velocity and pressure fields and they worked fine.

Code:

funkySetFields -field p -keepPatches -expression 'p/0.030625' -time 63 -condition "mag(vector(pos().x,pos().y,0))<=1.0"

Code:

funkySetFields -field U -keepPatches -expression 'U/0.175' -time 63 -condition "mag(vector(pos().x,pos().y,0))<=1.0"

However, when it comes to the surface scalar field 'phi', the error turned up like this:

Code:

--> FOAM FATAL ERROR:

 Parser Error for driver FieldValueExpressionDriver at "1.5-11" :"syntax error, unexpected number"

"phi/0.01575"

      ^^^^^^^

------|



Context of the error:





- Driver constructed from scratch

  Evaluating expression "phi/0.01575"





    From function parsingValue

    in file lnInclude/CommonValueExpressionDriverI.H at line 1081.

This is the code I use for phi:

Code:

funkySetFields -field phi -expression 'phi/0.01575' -time 63

Why I can't use funkySetFields for phi? Is there anything wrong in my code?

I really appreciate it if someone could give me a hand. Thank you very much.

Kind regards,
Tony

Quote:

Originally Posted by wzx1989221 (Post 480972)

Code:

funkySetFields -field p -keepPatches -expression 'p/0.030625' -time 63 -condition "mag(vector(pos().x,pos().y,0))<=1.0"

Code:

funkySetFields -field U -keepPatches -expression 'U/0.175' -time 63 -condition "mag(vector(pos().x,pos().y,0))<=1.0"

However, when it comes to the surface scalar field 'phi', the error turned up like this:

Code:

--> FOAM FATAL ERROR:

 Parser Error for driver FieldValueExpressionDriver at "1.5-11" :"syntax error, unexpected number"

"phi/0.01575"

      ^^^^^^^

------|



Context of the error:





- Driver constructed from scratch

  Evaluating expression "phi/0.01575"





    From function parsingValue

    in file lnInclude/CommonValueExpressionDriverI.H at line 1081.

This is the code I use for phi:

Code:

funkySetFields -field phi -expression 'phi/0.01575' -time 63

Why I can't use funkySetFields for phi? Is there anything wrong in my code?

I really appreciate it if someone could give me a hand. Thank you very much.

Kind regards,
Tony

You can. But phi is a surfaceScalarField and 0.01575 is (for technical reasons) a volScalarField. So 'phi/interpolate(0.01575)' should do the trick. Have a look at Documentation/swak4FoamReference.org for details.

BTW: for a condition you'll want to use fpos() for the face positions

Dear Bernhard,

Thank you very much for the solution and your kind notice.

I tried with interpolate() and it worked for internal fields, however, I couldn't change the values on the boundary (BTW, I am using cyclic boundary condition). Is it possible to get the flux value on boundary changed as well?

Thanks and regards,
Tony

Quote:

Originally Posted by wzx1989221 (Post 481189)

Currently no. The parser underneath funkySetFields only works on internalFields (and changing that requires a lot of work for that one application). funkySetBoundaryFields might work

Hi Bernhard,

Many thanks for your kind reply. I will have a look at that.

Kind regards,
Tony