[flowris]

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?

[boger]

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.

[flowris]

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!

[flowris]

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

    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?

[flowris]

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

[flowris]

Simply writing

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

results in the compiling error

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

[brdvolde]

Have you found a solution for this problem?

[giovastabile]

I have also the same problem

[louisgag]

Originally Posted by giovastabile

I have also the same problem

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

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

call directly from a solver?