applications/solvers/multiphase/twoLiquidMixingFoam/UEqn.H

   1     surfaceScalarField muf = twoPhaseProperties.muf();
   2
   3     fvVectorMatrix UEqn
   4     (
   5         fvm::ddt(rho, U)
   6       + fvm::div(rhoPhi, U)
   7       - fvm::laplacian(muf, U)
   8         //- (fvc::grad(U) & fvc::grad(muf))
   9       - fvc::div(muf*(mesh.Sf() & fvc::interpolate(fvc::grad(U)().T())))
  10     );
  11
  12     if (momentumPredictor)
  13     {
  14         solve
  15         (
  16             UEqn
  17          ==
  18            -fvc::reconstruct
  19             (
  20                 mesh.magSf()*(fvc::snGrad(pd) + ghf*fvc::snGrad(rho))
  21             )
  22         );
  23     }