UEqn.H

// Solve the Momentum equation
 
MRF.correctBoundaryVelocity(U);
 
fvVectorMatrix UEqn
(
    fvm::ddt(U) + fvm::div(phi, U)
    + MRF.DDt(U)
    + turbulence->divDevReff(U)
    ==
    fvOptions(U)
);
 
UEqn.relax();
 
fvOptions.constrain(UEqn);
 
if (piso.momentumPredictor())
{
    solve(UEqn == -fvc::grad(p));
    fvOptions.correct(U);
}