how to put if statement in between volScalarField and dimensionedScalar
 

Hi Foamers,

I have to put a if statement in between a volScalarField and dimensionedScalar. The part of the code is :

//////////////////////////////////////////////////////////////
volScalarField y = mesh.C().component(vector::Y);

volScalarField u = ustar*(((1.0-Y0)/(Y0-Foam::log(Y0)-1.0))*Foam::log(y)/(h*Y0)));

if(y >= Y0*h && y <= h )
{
u = ustar*(((1.0-Y0)/(Y0-Foam::log(Y0)-1.0))*Foam::log(y/(h*Y0)));
}
else
{
u = 0.0;
}

dimensionedScalar Y0
(
transportProperties.lookup("Y0")
);

dimensionedScalar h
(
transportProperties.lookup("h")
);

//////////////////////////////////////////////////////////////////////////


//////////////////////////////////////////////////////////////////////////
After running the code I'm getting this error :

.C:82:24: error: no match for ‘operator<=’ (operand types are ‘Foam::volScalarField {aka Foam::GeometricField<double, Foam::fvPatchField, Foam::volMesh>}’ and ‘Foam::dimensionedScalar {aka Foam::dimensioned<double>}’)
if(y >= Y0*h && y <= h )

you try to compare a value without dimensions with a value with dimensions,
so you are getting a dimension error. if you want to ignore it, which i do not recommend, you can just grab the values from both sides and compare the values. but the better way would be to fix the dimensions.

Finally I have fixed it. Here is the code, that works well.
forAll(mesh.C(), i)
{
if((y[i] >= Y0.value()*h.value()) && (y[i] <= h.value()) )
{
u[i] = ustar.value()*(((1.0-Y0.value())/(Y0.value()-Foam::log(Y0.value())-1.0))*Foam::log(y[i]/(h.value()*Y0.value())));
}
else
{
u[i] = 0.0;
}
}