UEqn.H

// Solve the Momentum equation
 
MRF.correctBoundaryVelocity(U);
 
tmp<fvVectorMatrix> tUEqn
(
    fvm::ddt(rho, U) + fvm::div(phi, U)
    + MRF.DDt(rho, U)
    + turbulence->divDevRhoReff(U)
    ==
    fvOptions(rho, U)
);
fvVectorMatrix& UEqn = tUEqn.ref();
 
UEqn.relax();
 
fvOptions.constrain(UEqn);
 
if (pimple.momentumPredictor())
{
    solve(UEqn == -fvc::grad(p));
    fvOptions.correct(U);
    K = 0.5 * magSqr(U);
}