This condition creates a zero-dimensional model of an enclosed volume of
gas upstream of the inlet. The pressure that the boundary condition
exerts on the inlet boundary is dependent on the thermodynamic state of
the upstream volume.  The upstream plenum density and temperature are
time-stepped along with the rest of the simulation, and momentum is
neglected. The plenum is supplied with a user specified mass flow and
temperature.

The result is a boundary condition which blends between a pressure inlet
condition condition and a fixed mass flow. The smaller the plenum
volume, the quicker the pressure responds to a deviation from the supply
mass flow, and the closer the model approximates a fixed mass flow. As
the plenum size increases, the model becomes more similar to a specified
pressure.

The expansion from the plenum to the inlet boundary is controlled by an
area ratio and a discharge coefficient. The area ratio can be used to
represent further acceleration between a sub-grid blockage such as fins.
The discharge coefficient represents a fractional deviation from an
ideal expansion process.

This condition is useful for simulating unsteady internal flow problems
for which both a mass flow boundary is unrealistic, and a pressure
boundary is susceptible to flow reversal. It was developed for use in
simulating confined combustion.

tutorials/compressible/rhoPimpleFoam/laminar/helmholtzResonance:
    helmholtz resonance tutorial case for plenum pressure boundary

This development was contributed by Will Bainbridge

Also added the new prghTotalHydrostaticPressure p_rgh BC which uses the
hydrostatic pressure field as the reference state for the far-field
which provides much more accurate entrainment is large open domains
typical of many fire simulations.

The hydrostatic field solution is controlled by the optional entries in
the fvSolution.PIMPLE dictionary, e.g.

    hydrostaticInitialization yes;
    nHydrostaticCorrectors 5;

and the solver must also be specified for the hydrostatic p_rgh field
ph_rgh e.g.

    ph_rgh
    {
        $p_rgh;
    }

Suitable boundary conditions for ph_rgh cannot always be derived from
those for p_rgh and so the ph_rgh is read to provide them.

To avoid accuracy issues with IO, restart and post-processing the p_rgh
and ph_rgh the option to specify a suitable reference pressure is
provided via the optional pRef file in the constant directory, e.g.

    dimensions      [1 -1 -2 0 0 0 0];
    value           101325;

which is used in the relationship between p_rgh and p:

    p = p_rgh + rho*gh + pRef;

Note that if pRef is specified all pressure BC specifications in the
p_rgh and ph_rgh files are relative to the reference to avoid round-off
errors.

For examples of suitable BCs for p_rgh and ph_rgh for a range of
fireFoam cases please study the tutorials in
tutorials/combustion/fireFoam/les which have all been updated.

Henry G. Weller
CFD Direct Ltd.

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=2060

Now the calculation of the 2nd-invariant is more efficient and
accumulates less round-off error.

Now internal forces and restraints may be applied between bodies within
the articulated structure.

The joint-space dynamics is solved on the master processor only and the
resulting joint-state distributed to the slave processors on which the
body-state is then updated.  This guarantees consistency of the body
position and orientation on all processors.

rigidBodyDynamics/bodies/sphere: Added support for the centre of mass being offset from the centre of rotation

Calculate the inertia from the lengths of the sides

Particularly useful for lists of dictionaries.

Patch provided by Bruno Santos
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=2036

See also http://www.openfoam.org/mantisbt/view.php?id=2036

Patch contributed by Bruno Santos
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=2052

rigidBodyMeshMotion: displacementMotionSolver for the mesh-motion of multiple articulated rigid-bodies

The motion of the bodies is integrated using the rigidBodyDynamics
library with joints, restraints and external forces.

The mesh-motion is interpolated using septernion averaging.

This development is sponsored by Carnegie Wave Energy Ltd.

Using method based on
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070017872.pdf
but simplified for the case where the quaternions are similar.

Patch contributed by Bruno Santos
Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=2055

inline Foam::vector Foam::septernion::transformPoint(const vector& v) const
{
    return r().transform(v - t());
}

Now there is a 1:1 correspondence between septernion and
spatialTransform and a septernion constructor from spatialTransform
provided.

Additionally "septernion::transform" has been renamed
"septernion::transformPoint" to clarify that it transforms coordinate
points rather than displacements or other relative vectors.

Replaced with 'unitQuaterion()' virtual function to indicate if the
joint uses a unit quaternion to represent rotation.

rigidBodyDynamics: Simplify handling of quaternions by maintaining a unit quaternion in the joint state field 'q'

'w' is now obtained from 'v' using the relation w = sqrt(1 - |sqr(v)|)
and 'v' is stored in the joint state field 'q' and integrated in the
usual manner but corrected using quaternion transformations.

    //- Return the unit quaternion (versor) from the given vector
    //  (w = sqrt(1 - |sqr(v)|))
    static inline quaternion unit(const vector& v);

rigidBodyDynamics/rigidBodySolvers: Added run-time selectable solvers to integrate the rigid-body motion

Currently supported solvers: symplectic, Newmark, CrankNicolson

The symplectic solver should only be used if iteration over the forces
and body-motion is not required.  Newmark and CrankNicolson both require
iteration to provide 2nd-order behavior.

See applications/test/rigidBodyDynamics/spring for an example of the
application of the Newmark solver.

This development is sponsored by Carnegie Wave Energy Ltd.

“Error when reading ascii data. Possible mismatch of datasize with
declaration.”

Patch contributed by Karl Meredith, FMGlobal

This is a more convenient way of maintaining the state or multiple
states (for higher-order integration), storing, retrieving and passing
between processors.

Included for backward-compatibility with the 6-DoF solver but in the
future will be re-implemented as a joint rather than body restraint and
accumulated in tau (internal forces) rather than fx (external forces).