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Using forces in other classes

Hello,

I have a mesh motion class that works very well for prescribed motion. I would like to use this class to do rigid body displacements, under the influence of the fluid forces. I can also calculate the forces using the standard forces function.

How can I take the results from this force calculation at each time step, and bring them into my mesh motion class for further use?

One way would be to instantiate a forces object from within your class and use the calcForcesMoment() method to get the forces and moments acting on your object.

Excellent! I saw that in the sixDoFRigidBodyDisplacement class, but was not sure if this was what I was looking for. I'll try and learn to use it.

Many thanks!

Do you know more about objectRegistry? I am trying to instantiate a forces object, as you suggested:

Code:

    dictionary forcesDict;



    forcesDict.add("patches", "block");

    forcesDict.add("rhoName", "rhoInf");

    forcesDict.add("rhoInf", 1000);

    vector centreOfMass_(0.0,0.0,0.0);

    forcesDict.add("CofR", centreOfMass_);



    forces f("forces", db(), forcesDict);

But in the last line, where is written "db()", I should put a reference to the objectRegistry. What is this, and how do I reference to it?

Can anybody tell me how to instantiate a forces object in a new class, or give an example where it is done?

Simply writing

Code:

forces f("forces", db(), forcesDict);

results in the compiling error

Code:

hppGgiFvMesh.C: In member function ‘void Foam::hppGgiFvMesh::getMoment()’:

hppGgiFvMesh.C:358: error: reference to ‘db’ is ambiguous

/home/jmatthei/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/IOobject.H:236: error: candidates are: const Foam::objectRegistry& Foam::IOobject::db() const

/home/jmatthei/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/IOobject.H:236: error:                 const Foam::objectRegistry& Foam::IOobject::db() const

/home/jmatthei/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/IOobject.H:236: error:                 const Foam::objectRegistry& Foam::IOobject::db() const

hppGgiFvMesh.C:358: error: reference to ‘db’ is ambiguous

/home/jmatthei/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/IOobject.H:236: error: candidates are: const Foam::objectRegistry& Foam::IOobject::db() const

/home/jmatthei/OpenFOAM/OpenFOAM-1.6-ext/src/OpenFOAM/lnInclude/IOobject.H:236: error:                 const Foam::objectRegistry& Foam::IOobject::db() const

Have you found a solution for this problem?

I have also the same problem

Quote:

Originally Posted by giovastabile (Post 615649)

I have also the same problem

And so do I, anyone knows how to access the db() objectRegistry required by the

Code:

forces f("forces", db(), forcesDict);

call directly from a solver?