Originally Posted by zippyhybrid

I'm not sure of a way to do that without having data files saved at previous time steps. I haven't used Fluent's tools to create animation, I've always saved contour plots as .png or .jpg images then used 3rd party tools to create animations. I create similar animations however since I am investigating air-lift driven flow and am interested in the behavior of bubbles in the airlift column. I'd suggest visualizing the interface using contours of phase and plot the contours of air ranging from 0 (water) to 1 (air).

Here is a sample journal file for a 2D simulation I ran in batch mode.

;read case and data
file/read-case single-48cm-2D-batchtest.cas
;
;initialize domain with air
/solve/initialize/initialize-flow
;
;patch water to raceway depth of 3.5 cm
/adapt/mark-inout-rectangle yes no 0 0.62875 -0.48 0.035
/solve/patch water () (0) mp 1
;
;set up image output
/display/set/contours/filled-contours yes
/display/set/picture/driver png
/display/set/picture/landscape yes
/display/set/picture/x-resolution 960
/display/set/picture/y-resolution 720
/display/set/picture/color-mode color
/views/restore-view front
;
;print front view of phases and velocity magnitude at t=0
/display/contour air vof 0 1
/display/save-picture airvof%t.png
/display/contour mixture velocity-magnitude 0 0.5
/display/save-picture velmag%t.png
;
;set up display commands to print front view of phases and velocity magnitude every 20 time steps
/solve/execute-commands/add-edit command-2 20 "time-step" "/display/contour air vof 0 1"
/solve/execute-commands/add-edit command-3 20 "time-step" "/display/save-picture airvof%t.png"
/solve/execute-commands/add-edit command-4 20 "time-step" "/display/contour mixture velocity-magnitude 0 0.5"
/solve/execute-commands/add-edit command-5 20 "time-step" "/display/save-picture velmag%t.png"
;
;set up auto-save
/file/auto-save data-frequency 500
/file/auto-save append-file-name-with time-step 6
;
;iterate over 5000 time steps
solve/set/time-step 0.001
solve/dual-time-iterate 5000 50
file/write-data single-48cm-2D-batchtest.dat