// Solve the Momentum equation fvVectorMatrix UEqn ( fvm::ddt(rho, U) + fvm::div(phi, U) + fvc::div ( (Alpha/(scalar(1.001) - Alpha))*(sqr(rhoc)/rho)*Vdj*Vdj, "div(phiVdj,Vdj)" ) - fvm::laplacian(mu, U, "laplacian(muEff,U)") ); if (pimple.momentumPredictor()) { solve ( UEqn == fvc::reconstruct ( ( - ghf*fvc::snGrad(rho) - fvc::snGrad(p) )*mesh.magSf() ) ); }