fvVectorMatrix UEqn ( fvm::ddt(U) + fvm::div(phi, U) + turbulence->divDevReff(U) ); UEqn.relax ( mesh.solutionDict().relaxationFactor(U.select(pimple.finalIter())) ); if (pimple.momentumPredictor()) { solve(UEqn == -fvc::grad(p)); }