First, I recommend doing some tutorials to get hands on. Do one single phase tutorial, then a second tutorial with Multiphase VOF (Volume of Fluid)nSecond, if you search this forum, you will find many posts on the same topic. They might be helpful to younThird, Assuming you have the geometry and mesh ready, in Ansys Fluent, you need to turn the gravity on (set the gravity -9.81 in the y direction and whatever exciting acceleration in the x direction) and use Multiphase Volume of Fluid. Select air and water as your fluids ... After initializing the case, you will batch air at the top and water at the bottom. nHere is a video on sloshing tank in Ansys Fluent and you will find a lot more videos on YoutubennnWelcome to CFD and Good Luck!n