[immortality]

in cases where there are compression or expansion waves its important to put the into account for calculating courant Number but it isn't in OpenFOAM code.why?
also there is a factor of .5 in equation.why it is there in formula?

#include "compressibleCourantNo.H"
#include "fvc.H"

Foam::scalar Foam::compressibleCourantNo
(
    const fvMesh& mesh,
    const Time& runTime,
    const volScalarField& rho,
    const surfaceScalarField& phi
)
{
    scalarField sumPhi
    (
        fvc::surfaceSum(mag(phi))().internalField()
      / rho.internalField()
    );

    scalar CoNum = 0.5*gMax(sumPhi/mesh.V().field())*runTime.deltaTValue();

    scalar meanCoNum =
        0.5*(gSum(sumPhi)/gSum(mesh.V().field()))*runTime.deltaTValue();

    Info<< "Region: " << mesh.name() << " Courant Number mean: " << meanCoNum
        << " max: " << CoNum << endl;

    return CoNum;
}

[immortality]

how should we account for wave speeds when they are important to us in the problem?
Any idea or guidance are be thanked.

[immortality]

do i understand right about courant number in openfoam?
Whats your opinion openfoamers?