[ali_hassan738]

Hello Foamers,
I have been trying to implement a velocity boundary condition in OpenFOAM v2012 following up the groovy boundary condition in swak4FOAM tutorial. As in v2012 there is #eval function instead of former #cal function to specify any function rather a value. I want to specify the inlet boundary condition of a parabola in a 2D pipe as

U = U_max (1 - (h/Total Height)^ 2)

vmax= 0.50
height = 0.40
inflow
{
type fixedValue;
value uniform #eval{
vector(($vmax * (1 - pow( pos().y/ $height ), 2) ,0 ,0))
};
}


The problem I am encountering is that the #eval function is prompting a syntax error as:

--> FOAM FATAL IO ERROR: (openfoam-2012)

Syntax error in expression at position:33
<<<<
vector((0.5000000 * (1 - pow(pos().y/ 0.4000000),2),0,0))
^^^^ near here

>>>>


From void Foam:arsing::genericRagelLemonDriver::reportFata l(const string&, size_t) const
in file primitives/strings/parsing/genericRagelLemonDriver.C at line 170.

FOAM exiting

whereas formerly this boundary condition works fine with the groovyBC. I am sure I am missing some information in the syntax.

Any help in this regard will be appreciated.

[Aditya Rathore]

Did you get the solution? I am getting the same error.

[olesen]

Originally Posted by ali_hassan738

Hello Foamers,
I have been trying to implement a velocity boundary condition in OpenFOAM v2012 following up the groovy boundary condition in swak4FOAM tutorial. As in v2012 there is #eval function instead of former #cal function to specify any function rather a value. I want to specify the inlet boundary condition of a parabola in a 2D pipe as

U = U_max (1 - (h/Total Height)^ 2)

vmax= 0.50
height = 0.40
inflow
{
type fixedValue;
value uniform #eval{
vector(($vmax * (1 - pow( pos().y/ $height ), 2) ,0 ,0))
};
}


The problem I am encountering is that the #eval function is prompting a syntax error as:

--> FOAM FATAL IO ERROR: (openfoam-2012)

Syntax error in expression at position:33
<<<<
vector((0.5000000 * (1 - pow(pos().y/ 0.4000000),2),0,0))
^^^^ near here

>>>>


From void Foam:arsing::genericRagelLemonDriver::reportFata l(const string&, size_t) const
in file primitives/strings/parsing/genericRagelLemonDriver.C at line 170.

FOAM exiting

whereas formerly this boundary condition works fine with the groovyBC. I am sure I am missing some information in the syntax.

Any help in this regard will be appreciated.

You are mixing way too many things. The #eval directive is a direct expression evaluation without any mesh information. So you can't start putting in something like pos().y() and expect anything useful to happen. For this type of thing you would normally want to use a uniformFixedValue BC and specify that the PatchFunction1 is an expression type. If you do that you will then have access to mesh data - eg, the face centres as pos() - and other things like time() etc. Note, however, that your original equation had a stray ", 2)," in the middle it seems.