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.
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.
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.
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.
'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.
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.
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).
applications/test/rigidBodyDynamics/spring: Test of the linear spring with damper restraint
Damped simple harmonic motion of a weight on a spring is simulated and
the results compared with analytical solution
Test-spring
gnuplot spring.gnuplot
evince spring.eps
This development is sponsored by Carnegie Wave Energy Ltd.
