On mesh_motion of cross section in fluid structure interaction (DC-FSI) with Acusolve and Optistruct

We are simulating the pressure propagation of a fluid flowing through an elastic pipe using fluid-structure interaction between Acusolve and Optistruct.

I would appreciate it if you could answer the following questions.
The first is the handling of mesh_motion in Acu-OptFSI.

I would also like to ask an additional question,
An additional question is about setting non-reflective boundary conditions in Acusolve.

Below is a PDF file for your explanation.

Thank you in advance.

QuestionSlide2.pdf

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acupro

Thank you for your reply. Attached below is the inp. file (3_2_flu.inp) of the simulation model.

There should be no need for Interface-Surface here - as that is for cases where the meshes are disconnected. It seems this mesh should be all simply connected - with the two volumes on either side of that internal surface (for output purposes only) sharing the same single set of nodes.

I would try applying Planar Slip or No Constraints to that internal surface - under Motion > Constraints.

Even simpler might be commenting out the entire SIMPLE_BOUNDARY_CONDITION command where the type = auto_wall from the input file. (Then you'll need to use the AcuSolve Command Prompt or Compute Manager to run with that edited input file.) It looks like the only surface sets remaining there are those for that internal measurement surface. I would try this first. The mesh may distort a bit depending on how the outer wall deforms - but you should still get reasonable surface output results.

All comments

acupro

Can you please attach just the AcuSolve input (.inp) file?

Motoki_Koga

Thank you for your reply. Attached below is the inp. file (3_2_flu.inp) of the simulation model.

3_2_flu.inp

acupro

Thank you for your reply. Attached below is the inp. file (3_2_flu.inp) of the simulation model.

I would try applying Planar Slip or No Constraints to that internal surface - under Motion > Constraints.

Motoki_Koga

There should be no need for Interface-Surface here - as that is for cases where the meshes are disconnected. It seems this mesh should be all simply connected - with the two volumes on either side of that internal surface (for output purposes only) sharing the same single set of nodes.

I would try applying Planar Slip or No Constraints to that internal surface - under Motion > Constraints.

Even simpler might be commenting out the entire SIMPLE_BOUNDARY_CONDITION command where the type = auto_wall from the input file. (Then you'll need to use the AcuSolve Command Prompt or Compute Manager to run with that edited input file.) It looks like the only surface sets remaining there are those for that internal measurement surface. I would try this first. The mesh may distort a bit depending on how the outer wall deforms - but you should still get reasonable surface output results.

I commented out the SIMPLE_BOUNDARY_CONDITION for auto_wall and re-created the cross section of the simulation model and was able to start the calculation successfully. We also set up surface_monitor and were able to verify that the area values at certain cross sections were changing. This allowed us to output cross sections under the condition of interaction.

I would also appreciate it if you could tell me how to set the non_reflectiong_boundary_condition_runnning_average_field to true regarding the non_reflection_boundary_conditon.

Once again, thank you for your reply.

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