
For timedependent VOF calculations, Equation 22.21 is solved using an explicit timemarching scheme. FLUENT automatically refines the time step for the integration of the volume fraction equation, but you can influence this time step calculation by modifying the Courant number. You can choose to update the volume fraction once for each time step, or once for each iteration within each time step. These options are discussed in more detail in Section 22.6.14.