applications/solvers/combustion/dieselEngineFoam/UEqn.H

   1     fvVectorMatrix UEqn
   2     (
   3         fvm::ddt(rho, U)
   4       + fvm::div(phi, U)
   5       + turbulence->divDevRhoReff(U)
   6      ==
   7         rho*g
   8       + dieselSpray.momentumSource()
   9     );
  10
  11     if (momentumPredictor)
  12     {
  13         solve(UEqn == -fvc::grad(p));
  14     }