Jakob Baldwin uses Sketchfab's stop-motion feature to publish his Blender fluid simulations.
Fluid simulation can be tricky to create, really difficult to make realistic and it’s not really possible to upload and display natively on Sketchfab, but there is a workaround.
Here is an example of fluid simulation in Sketchfab:
This tutorial is meant for Blender, but the general principle works for all 3D applications. In short, Sketchfab supports stop-motion animation: if you upload a .zip file with several objects and a .timeframe text file, Sketchfab will display the models in stop motion. If you export every frame of a fluid simulation as a separate .obj, it can then be displayed on Sketchfab.