FLUENT6: How to plot the velocity vectors inside one particular phase in VOF simulation?
While displaying the velocity vectors it displays the velocity vector for all phases. Is it possible to show the velocity vectors inside only one phase at a time? Solution: FLUENT solves single momentum equation for mixture only and resulting velocity field is shared among the phases. Hence, the vectors are plotted for all the phases at the same time. Following steps can be used to show the velocity vectors for a particular phase in a two phase system. 1. Create a Custom field function (CFF), vx_phase1 = X velocity * Volume fraction of particular phase using Define > Custom Field Function panel. As Volume fraction will be 1 inside the phase and zero outside, vx_phase1 will have same value as vx inside phase and zero value outside. 2. Similarly, create the two more CFFs: vy_phase1 and vz_phase2. 3. Now, draw the custom vectors using vx_phase1, vy_phase1 and vz_phase1 as X and Y component of the custom vectors. Please note that at the interface where volume fraction is between 0 and 1, the vectors may not be accurate. 

