How to use y_ as dimensionless argument?

klausb · February 19, 2016, 15:41

Hello,

I want to extend the function to calculate nut_ by multiplication with 0.1*tanh(pow((0.003*y_),6)).

nut_ = ((existing function)*(0.1*tanh(pow((0.003*y_),6))));

Compilation works fine but when I use the new turbulence model, I get an error:
[0] --> FOAM FATAL ERROR:
[0] Argument of trancendental function not dimensionless
[0]
[0] From function trans(const dimensionSet&)
[0] in file dimensionSet/dimensionSet.C at line 430.
[0]
FOAM parallel run aborting
...

I assume y_ is not a dimensionless argument for tanh().

How can I deal with that?

Klaus

alexeym · February 19, 2016, 15:53

Hi,

You can do something like:

Code:

dimensionedScalar unitY_("y_", y_.dimensions(), 1.0);

nut_ = ((existing function)*(0.1*tanh(pow((0.003*y_/unitY_),6))));

jherb · February 23, 2016, 05:09

Have you tried y_.value()?

February 19, 2016, 15:41	How to use y_ as dimensionless argument?	#1
klausb Senior Member Klaus Join Date: Mar 2009 Posts: 250 Rep Power: 22	Hello, I want to extend the function to calculate nut_ by multiplication with 0.1tanh(pow((0.003y_),6)). nut_ = ((existing function)(0.1tanh(pow((0.003*y_),6)))); Compilation works fine but when I use the new turbulence model, I get an error: [0] --> FOAM FATAL ERROR: [0] Argument of trancendental function not dimensionless [0] [0] From function trans(const dimensionSet&) [0] in file dimensionSet/dimensionSet.C at line 430. [0] FOAM parallel run aborting ... I assume y_ is not a dimensionless argument for tanh(). How can I deal with that? Klaus Luttappy likes this.

February 19, 2016, 15:53		#2
alexeym Senior Member Alexey Matveichev Join Date: Aug 2011 Location: Nancy, France Posts: 1,930 Rep Power: 38	Hi, You can do something like: Code: dimensionedScalar unitY_("y_", y_.dimensions(), 1.0); nut_ = ((existing function)(0.1tanh(pow((0.003*y_/unitY_),6))));

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February 23, 2016, 05:09		#3
jherb Senior Member Joachim Herb Join Date: Sep 2010 Posts: 650 Rep Power: 21	Have you tried y_.value()?