CFD Online Discussion Forums - momentum equation in rhoCentralFoam

its the momemntum equation in rhoCentralFoam.
what are equivalents for its terms in CFD form?

Code:

solve

            (

                fvm::ddt(rho, U) - fvc::ddt(rho, U)

              - fvm::laplacian(muEff, U)

              - fvc::div(tauMC)

            );

in rhoPimpleFoam its so:

Code:

tmp<fvVectorMatrix> UEqn

(

    fvm::ddt(rho, U)

  + fvm::div(phi, U)

  + turbulence->divDevRhoReff(U)

 ==

    fvOptions(rho, U)

);



UEqn().relax();



fvOptions.constrain(UEqn());



if (pimple.momentumPredictor())

{

    solve(UEqn() == -fvc::grad(p));



    fvOptions.correct(U);

    K = 0.5*magSqr(U);

}

that the temporal,convection and diffusion and source terms are more clear than in rhoCentralFoam.