applications/solvers/multiphase/twoPhaseEulerFoam/DDtU.H

   1 {
   2     DDtUa =
   3         fvc::ddt(Ua)
   4       + fvc::div(phia, Ua)
   5       - fvc::div(phia)*Ua;
   6
   7     DDtUb =
   8         fvc::ddt(Ub)
   9       + fvc::div(phib, Ub)
  10       - fvc::div(phib)*Ub;
  11 }