Hello,

In my model, I've got a box which is filled with a fluid (fluid-structure-interaction). It is fixed on the ground and I'm giving an impulse on the top of the box to analyse the oscillation.
The problem is that the fluid separates from the box and therefore the oscillation of the box isn't damped by the fluid.
I think the solution would be to remove the tick of 'allow separation after contact' in the interaction properties, but when I do this Abaqus says "at least one non-blank surface must be defined for contact interactions". What does it mean? I'm using the option 'Hard Contact'.
I would be very happy about an answer.

With Best Regards,
Max