Learning Forum

[ghazwansa]

Hello ANSYS experts,

I have a moving box that has fluid inside it. The box is closed and moves according to a pre-defined motion plan. I also want to study the stresses generated in the box's walls, hence there is the coupling part.

I have prepared the system and all the coupling portion with "Transient Structural" setup, but I am getting an error during the first iteration.

I think there is a problem with the way I need to define the attachment between the deforming and moving walls and the fluid domain. It should have the two components, it is moving and it is deforming, and from what I understand, I only know how to create the fluid-structure interaction dynamic mesh zone. Do you think this by default should handle the moving wall? Or do I need to add another definition for the fluid domain?

Any ideas on how to handle this? 

Thank you,

[peteroznewman]

I'm curious if the fluid is a single phase. Is the box filled completely with liquid with no air at the top? Because if there was a free surface inside, then that would allow sloshing and all kinds of complications.

If the box is completely filled with liquid, then that has a very high bulk modulus relative to the flexible walls of the box. I have done Transient Structural models with a container filled with water and I didn't need Fluent at all. I just made a solid that had the bulk modulus of water and very low shear. That was sufficient to simulate a Drop Test of the water-filled container.

Regards,

Peter

[ghazwansa]

Hi Peter,

It is single phase and completely filled. This "box" is actually a simplified version of another study that has more complicated geometry. The idea is to study the effect of the fluid inertia, and at which box acceleration there will be a vacuum pressure on one side of the box. Meaning, it is essential to keep the material as fluid inside the box.

Thanks