The boundary conditions of HbyA are now constrained by the new "constrainHbyA"
function which applies the velocity boundary values for patches for which the
velocity cannot be modified by assignment and pressure extrapolation is
not specified via the new
"fixedFluxExtrapolatedPressureFvPatchScalarField".
The new function "constrainPressure" sets the pressure gradient
appropriately for "fixedFluxPressureFvPatchScalarField" and
"fixedFluxExtrapolatedPressureFvPatchScalarField" boundary conditions to
ensure the evaluated flux corresponds to the known velocity values at
the boundary.
The "fixedFluxPressureFvPatchScalarField" boundary condition operates
exactly as before, ensuring the correct flux at fixed-flux boundaries by
compensating for the body forces (gravity in particular) with the
pressure gradient.
The new "fixedFluxExtrapolatedPressureFvPatchScalarField" boundary
condition may be used for cases with or without body-forces to set the
pressure gradient to compensate not only for the body-force but also the
extrapolated "HbyA" which provides a second-order boundary condition for
pressure. This is useful for a range a problems including impinging
flow, extrapolated inlet conditions with body-forces or for highly
viscous flows, pressure-induced separation etc. To test this boundary
condition at walls in the motorBike tutorial case set
lowerWall
{
type fixedFluxExtrapolatedPressure;
}
motorBikeGroup
{
type fixedFluxExtrapolatedPressure;
}
Currently the new extrapolated pressure boundary condition is supported
for all incompressible and sub-sonic compressible solvers except those
providing implicit and tensorial porosity support. The approach will be
extended to cover these solvers and options in the future.
Note: the extrapolated pressure boundary condition is experimental and
requires further testing to assess the range of applicability,
stability, accuracy etc.
Henry G. Weller
CFD Direct Ltd.
Drag model for gas-liquid system of Tomiyama et al.
Reference:
"Drag coefficients of single bubbles under normal and microgravity
conditions"
Tomiyama, A., Kataoka, I., Zun, I., Sakaguchi, T.
JSME International Series B, Fluids and Thermal Engineering,
Vol. 41, 1998, pp. 472-479
Provided by Alberto Passalacq
It is better to declare the namespace of each function in the C file
rather than "open" the namespace as this may lead to inconsistencies
between the declaration in the H files and definition in the C file.
fvOptions are transferred to the database on construction using
fv::options::New which returns a reference. The same function can be
use for construction and lookup so that fvOptions are now entirely
demand-driven.
The abstract base-classes for fvOptions now reside in the finiteVolume
library simplifying compilation and linkage. The concrete
implementations of fvOptions are still in the single monolithic
fvOptions library but in the future this will be separated into smaller
libraries based on application area which may be linked at run-time in
the same manner as functionObjects.
across all the phases in an Eulerian multi-phase simulation.
Intended to be used with copiedFixedValue to ensure that phase wall
temperature are consistent:
- Set 'fixedMultiPhaseHeatFlux' boundary for one of the phases
- Use 'copiedFixedValue' for all the other phases.
Based on code provided by Juho Peltola
Provides run-time selection of buoyancy sources for compressible solvers
Replaces the built-in buoyancy sources in XiFoam, reactingFoam and
rhoReactingFoam.
e.g. in constant/fvOptions specify
momentumSource
{
type buoyancyForce;
buoyancyForceCoeffs
{
fieldNames (U);
}
}
and optionally specify the buoyancy energy source in the enthalpy
equation:
energySource
{
type buoyancyEnergy;
buoyancyEnergyCoeffs
{
fieldNames (h);
}
}
or internal energy equation
energySource
{
type buoyancyEnergy;
buoyancyEnergyCoeffs
{
fieldNames (e);
}
}
New lift model supporting near-wall damping using the new
wallDampingModels.
e.g.
lift
(
(air in water)
{
type wallDamped;
lift
{
type constantCoefficient;
Cl 0.5;
}
wallDamping
{
type linear;
Cd 0.5;
}
}
);
in which a linear near-wall damping function min(y/(Cd*d), 1) is applied to the constant
coefficient lift model. Additional wall-damping functions will be added.
to allow iteration over the energy equations to improve stability for phase-change.
Additionally if nEnergyCorrectors is set to 0 the energy equations are
not solved which may be beneficial during the startup of some cases.
Now solvers return solver performance information for all components
with backward compatibility provided by the "max" function which created
the scalar solverPerformance from the maximum component residuals from
the SolverPerformance<Type>.
The residuals functionObject has been upgraded to support
SolverPerformance<Type> so that now the initial residuals for all
(valid) components are tabulated, e.g. for the cavity tutorial case the
residuals for p, Ux and Uy are listed vs time.
Currently the residualControl option of pimpleControl and simpleControl
is supported in backward compatibility mode (only the maximum component
residual is considered) but in the future this will be upgraded to
support convergence control for the components individually.
This development started from patches provided by Bruno Santos, See
http://www.openfoam.org/mantisbt/view.php?id=1824
