// Solve the momentum equation Urel.storePrevIter(); fvVectorMatrix UrelEqn ( fvm::ddt(rho, Urel) + fvm::div(phi, Urel) + turbulence->divDevRhoReff() + rho*SRF->Su() ); UrelEqn.relax(); solve(UrelEqn == -fvc::grad(p));