Access to field data

sepp · February 10, 2011, 09:59

hello
Probably I got a very simple question, but I'm new at openfoam and so I don't see the problem.

I'm working with icoFoam and in icoFoam I'm able to display each component of U:
Pout<< icoFoam.C u: " << U.internalField()[0][0] << endl;

then icoFoam calls fvm::div, which can also display each one: (U is now named vf)
Pout<<"fvmDiv.C div1 u:" << vf.internalField()[0][0] << endl;

div calls convectionScheme<Type>::New(vf.mesh(),flux,vf.mesh ().divScheme(name) )().fvmDiv(flux, vf), which calls gaussConvectionScheme.

and there I'm not able to access
Pout<<"gaussConvectionScheme.C fvmdiv1 u:" << vf.internalField()[0][0] << endl;

what's the reason for being able to access to vf.internalField()[0], but not to vf.internalField()[0][0] ?

thanks for your help

Bernhard · February 10, 2011, 10:29

I'm not sure what you want to reach here? Maybe you can explain it, because most likely there is a much easier solution.

Anyhow, the divergence of a vector gives you a scalar, so div(U) has no vector-components.

sepp · February 10, 2011, 11:45

Well, the thing I should do is to implement an alternative way of calculating the convection term.

The calculation is made by an scheme invonked by gaussConvectionScheme. (It's not my idea but I've got to do it). In this scheme I've got to do some calculations with U-values. These values are imparted from icoFoam to fvmDiv and so on in a geometricField. There's nowhere any manipulation but beginning at gaussConvectionScheme I cannot access each component of the U vectors. I can do addition and multiplikation with scalars on the hole vector, but nothing for example on the x value of U.

I can do my calculation with an U-value from the lookup table, but then the return value has the wrong type.

typeid(vf.internalField()[0][0]).name() gave me "d" as datatype of this. Is there in OpenFoam a datatype d?

February 10, 2011, 09:59	Access to field data	#1
sepp New Member johannes Join Date: Feb 2011 Posts: 7 Rep Power: 15	hello Probably I got a very simple question, but I'm new at openfoam and so I don't see the problem. I'm working with icoFoam and in icoFoam I'm able to display each component of U: Pout<< icoFoam.C u: " << U.internalField()[0][0] << endl; then icoFoam calls fvm::div, which can also display each one: (U is now named vf) Pout<<"fvmDiv.C div1 u:" << vf.internalField()[0][0] << endl; div calls convectionScheme<Type>::New(vf.mesh(),flux,vf.mesh ().divScheme(name) )().fvmDiv(flux, vf), which calls gaussConvectionScheme. and there I'm not able to access Pout<<"gaussConvectionScheme.C fvmdiv1 u:" << vf.internalField()[0][0] << endl; what's the reason for being able to access to vf.internalField()[0], but not to vf.internalField()[0][0] ? thanks for your help

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February 10, 2011, 10:29		#2
Bernhard Senior Member Bernhard Join Date: Sep 2009 Location: Delft Posts: 790 Rep Power: 21	I'm not sure what you want to reach here? Maybe you can explain it, because most likely there is a much easier solution. Anyhow, the divergence of a vector gives you a scalar, so div(U) has no vector-components.

February 10, 2011, 11:45		#3
sepp New Member johannes Join Date: Feb 2011 Posts: 7 Rep Power: 15	Well, the thing I should do is to implement an alternative way of calculating the convection term. The calculation is made by an scheme invonked by gaussConvectionScheme. (It's not my idea but I've got to do it). In this scheme I've got to do some calculations with U-values. These values are imparted from icoFoam to fvmDiv and so on in a geometricField. There's nowhere any manipulation but beginning at gaussConvectionScheme I cannot access each component of the U vectors. I can do addition and multiplikation with scalars on the hole vector, but nothing for example on the x value of U. I can do my calculation with an U-value from the lookup table, but then the return value has the wrong type. typeid(vf.internalField()[0][0]).name() gave me "d" as datatype of this. Is there in OpenFoam a datatype d?