const surfaceScalarField & tauQGDf
volVectorField W(IOobject("W", runTime.timeName(), mesh, IOobject::NO_READ, IOobject::NO_WRITE), U)
volScalarField rho(IOobject("rho", runTime.timeName(), mesh, IOobject::NO_READ, IOobject::AUTO_WRITE), thermo.rho())
volVectorField U(IOobject("U", runTime.timeName(), mesh, IOobject::MUST_READ, IOobject::AUTO_WRITE), mesh)