24.5.3 Setting Time-Dependent Parameters for the Explicit Volume Fraction Scheme

If you are using the time-dependent volume fraction formulation in ANSYS FLUENT, an explicit solution for the volume fraction is obtained either once each time step or once each iteration, depending upon your inputs to the model. By default, ANSYS FLUENT will solve the volume fraction equation(s) once for each time step, except for the first time step. This means that the convective flux coefficients appearing in the other transport equations will not be completely updated each iteration, since the volume fraction fields will not change from iteration to iteration.

This formulation also applies to the VOF model, and is discussed in greater detail in Section  24.3.5.