applications/solvers/compressible/rhoPisoFoam/UEqn.H

   1     fvVectorMatrix UEqn
   2     (
   3         fvm::ddt(rho, U)
   4       + fvm::div(phi, U)
   5       + turbulence->divDevRhoReff(U)
   6     );
   7
   8     if (momentumPredictor)
   9     {
  10         solve(UEqn == -fvc::grad(p));
  11     }