Having trouble getting a circle to fall through water
 

Hello,

I'm trying to get a circle to fall through air into water where it will float. I am creating my mesh using ANSYS Workbench (which I have to use) and exporting it as a .msh file. I then start up FLUENT, load the mesh file and set up the system in the same way as a tutorial I have done which had a falling box. However I get major problems with mine as you can see in the pictures attached.

The only difference I can see (apart from it being a circle instead of a box) is that in the tutorial their box was inside a slightly bigger box and they fell together but if my understanding is correct I shouldn't need that second box. I tried to create it but I'm not good at using design modeler and couldn't get it to put circle inside a box inside a box without it subtracting the area between the circle and the smaller box.

Can anyone see what I'm doing wrong and is there anymore info you need to help?

I'm using:
ANSYS 12
Workbench - Design Modeler
Workbench - Meshing
FLUENT