[babala]

Hello everyone,
I'm try to write a new pressure BC in OpenFoam.In this BC, I need to use velocity. So I use the code
"const volVectorField& U = db().lookupObject<volVectorField>("U");"
to get the information of U into the BC.
The BC has been compiled successfully. but when I use it in a case, the solver show an error below:
--------------------------------------------------------------------
Reading field p

--> FOAM FATAL ERROR:
request for volVectorField U from objectRegistry region0 failed
available objects of type volVectorField are
0
(
)

From function objectRegistry::lookupObject<Type>(const word&) const
in file /home/lizhy1/OpenFOAM/OpenFOAM-2.2.2/src/OpenFOAM/lnInclude/objectRegistryTemplates.C at line 164.
FOAM aborting
----------------------------------------------------------------------
I don't know how to solve this problem. Please Help me!
Any help will be appreciated.

[ThomasV]

While I cannot help as I'm introducing myself into writing BCs too I'd like to extend the question. When looking at OpenFoam's code one can find segments like this:

const fvPatchScalarField& kp =
 patch().lookupPatchField<volScalarField, scalar>(kName_);

What are those private "kName_" obejcts needed for? It's basically just this...

//- Name of the turbulent kinetic energy field                                        word
  word kName_;

... and it's defined in the constructors like this:

kName_(dict.lookupOrDefault<word>("k", "k"))

So can't we just look up the values like it's described in the opening posting of this thread and have to use words and a lookup<word> method for this instead?