Contribution provided by Bruno Santos
Resolves feature request http://www.openfoam.org/mantisbt/view.php?id=2004

This change requires that the de-reference operator '()' returns a
const-reference to the object stored irrespective of the const-ness of
object stored and the new member function 'ref()' is provided to return
an non-const reference to stored object which throws a fatal error if the
stored object is const.

In order to smooth the transition to this new safer 'tmp' the now
deprecated and unsafe non-const de-reference operator '()' is still
provided by default but may be switched-off with the compilation switch
'CONST_TMP'.

The main OpenFOAM library has already been upgraded and '-DCONST_TMP'
option specified in the 'options' file to switch to the new 'tmp'
behavior.  The rest of OpenFOAM-dev will be upgraded over the following
few weeks.

Henry G. Weller
CFD Direct

To be used instead of zeroGradientFvPatchField for temporary fields for
which zero-gradient extrapolation is use to evaluate the boundary field
but avoiding fields derived from temporary field using field algebra
inheriting the zeroGradient boundary condition by the reuse of the
temporary field storage.

zeroGradientFvPatchField should not be used as the default patch field
for any temporary fields and should be avoided for non-temporary fields
except where it is clearly appropriate;
extrapolatedCalculatedFvPatchField and calculatedFvPatchField are
generally more suitable defaults depending on the manner in which the
boundary values are specified or evaluated.

The entire OpenFOAM-dev code-base has been updated following the above
recommendations.

Henry G. Weller
CFD Direct

Vastly reduces the scattering and churning behaviour of packed beds.

Development provided by Will Bainbridge <github.com/will-bainbridge>

See also http://www.openfoam.org/mantisbt/view.php?id=1994

Resolves bug-report http://www.openfoam.org/mantisbt/view.php?id=1995

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.

which returns true if the fvPatchField type provides an assignment operator

valuePointPatchField: Change assignment to use the object's internalField rather than that of the argument

Avoids dependency on the state of the argument pointPatchField the
internalField of which may have been de-allocated

which supports re-using the internalField storage

This is a convenient method to set a null-constructed tmp in a
conditional statement.

Resolved bug-report http://www.openfoam.org/mantisbt/view.php?id=1990

with optional specification of the mark/space ratio

    Templated square-wave function with support for an offset level.

        \f[
            a square(f (t - t_0)) s + l
        \f]

    where

    \f$ square(t) \f$ is the square-wave function in range \f$ [-1, 1] \f$
    with a mark/space ratio of \f$ r \f$

    \vartable
        symbol  | Description       | Data type         | Default
        a       | Amplitude         | Function1<scalar> |
        f       | Frequency [1/s]   | Function1<scalar> |
        s       | Type scale factor | Function1<Type>   |
        l       | Type offset level | Function1<Type>   |
        t_0     | Start time [s]    | scalar            | 0
        r       | mark/space ratio  | scalar            | 1
        t       | Time [s]          | scalar
    \endvartable

    Example for a scalar:
    \verbatim
        <entryName> square;
        <entryName>Coeffs
        {
            frequency 10;
            amplitude 0.1;
            scale     2e-6;
            level     2e-6;
        }
    \endverbatim

to support time-variation

to support time-variation

noSlip is equivalent to fixedValue with a value of (0 0 0) but is
simpler to specify e.g.

     upperWall
     {
         type            noSlip;
     }

movingWallVelocityFvPatchVectorField: Updated to obtain the velocity field from the dimensionedInteralField
rather than by "lookup" from the database.

For example the sinusoidal motion of the floating object in the
potentialFreeSurfaceFoam/oscillatingBox tutorial is now specified thus

    floatingObject
    {
        type            fixedNormalInletOutletVelocity;

        fixTangentialInflow false;

        normalVelocity
        {
            type            uniformFixedValue;
            uniformValue    sine;
            uniformValueCoeffs
            {
                frequency 1;
                amplitude table
                (
                    (   0     0)
                    (  10 0.025)
                    (1000 0.025)
                );
                scale     (0 1 0);
                level     (0 0 0);
            }
        }

        value           uniform (0 0 0);
    }

rather than using

    floatingObject
    {
        type            fixedNormalInletOutletVelocity;

        fixTangentialInflow false;

        normalVelocity
        {
            type            oscillatingFixedValue;
            refValue        uniform (0 1 0);
            offset          (0 -1 0);
            amplitude       table
            (
                (   0     0)
                (  10 0.025)
                (1000 0.025)
            );
            frequency       constant 1;
        }

        value           uniform (0 0 0);
    }

    Templated sine function with support for an offset level.

        \f[
            a sin(2 \pi f (t - t_0)) s + l
        \f]

    where

    \vartable
        symbol  | Description       | Data type
        a       | Amplitude         | Function1<scalar>
        f       | Frequency [1/s]   | Function1<scalar>
        s       | Type scale factor | Function1<Type>
        l       | Type offset level | Function1<Type>
        t_0     | Start time [s]    | scalar
        t       | Time [s]          | scalar
    \endvartable

Function1 is an abstract base-class of run-time selectable unary
functions which may be composed of other Function1's allowing the user
to specify complex functions of a single scalar variable, e.g. time.
The implementations need not be a simple or continuous functions;
interpolated tables and polynomials are also supported.  In fact form of
mapping between a single scalar input and a single primitive type output
is supportable.

The primary application of Function1 is in time-varying boundary
conditions, it also used for other functions of time, e.g. injected mass
is spray simulations but is not limited to functions of time.

Description
    Templated sine function with support for an offset level.

        \f[
            a sin(2 \pi f (t - t_0)) s + l
        \f]

    where

    \vartable
        a       | Amplitude
        f       | Frequency [1/s]
        s       | Type scale factor
        l       | Type offset level
        t_0     | Start time [s]
        t       | Time [s]
    \endvartable

    Example for a scalar:
    \verbatim
        <entryName> sine;
        <entryName>Coeffs
        {
            frequency 10;
            amplitude 0.1;
            scale     2e-6;
            level     2e-6;
        }
    \endverbatim

    Example for a vector:
    \verbatim
        <entryName> sine;
        <entryName>Coeffs
        {
            frequency 10;
            amplitude 1;
            scale     (1 0.1 0);
            level     (10 1 0);
        }
    \endverbatim