Updating fvSolution's for closed domains for chtMultiRegionFoam cases

Henry Weller authored 7 years ago and Andrew Heather committed 7 years ago

79ff91350 - rhoPimpleFoam: Improved support for compressible liquids
(2017-05-17 17:05:43 +0100) <Henry Weller>

e.g. (fvc::interpolate(HbyA) & mesh.Sf()) -> fvc::flux(HbyA)

This removes the need to create an intermediate face-vector field when
computing fluxes which is more efficient, reduces the peak storage and
improved cache coherency in addition to providing a simpler and cleaner
API.

The deprecated non-const tmp functionality is now on the compiler switch
NON_CONST_TMP which can be enabled by adding -DNON_CONST_TMP to EXE_INC
in the Make/options file.  However, it is recommended to upgrade all
code to the new safer tmp by using the '.ref()' member function rather
than the non-const '()' dereference operator when non-const access to
the temporary object is required.

Please report any problems on Mantis.

Henry G. Weller
CFD Direct.

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.

Pressure relaxation is useful with LTS to damp acoustic waves

fvOptions does not have the appropriate structure to support MRF as it
is based on option selection by user-specified fields whereas MRF MUST
be applied to all velocity fields in the particular solver.  A
consequence of the particular design choices in fvOptions made it
difficult to support MRF for multiphase and it is easier to support
frame-related and field related options separately.

Currently the MRF functionality provided supports only rotations but
the structure will be generalized to support other frame motions
including linear acceleration, SRF rotation and 6DoF which will be
run-time selectable.

fixedFluxPressure BC: the snGrad is now pushed into the BC from pEqn.H rather than being evaluated in the BC

For DyM solvers phiAbs is replaced by Uf but this conversion is currently not complete

so that the effect of the term on the enthalpy equation is optional

     sensible enthalpy thermo packages

- Enthalpy source term now retrieved from the chemistry model (scaled by
  kappa for the PaSR model)