[omkar5990]

Hello all,

I am new to FSI and have been working on a problem that involves a deformable pipe in ANSYS 19.2. The length of the pipe is 20 mm and the internal diameter is 3 mm. The thickness of the pipe is 1 mm. I am trying to simulate flow of water in the pipe for the case when the rear portion of the pipe (last 5 mm ) is made up of a more compliant material and has a pulsating external pressure being applied to it. Water flows into the pipe at 0.5 m/s for which I have used a velocity-inlet condition. What I am hoping to achieve is that due to deformation of the pipe at the rear end, there is reversal of water flow and it flows back towards the inlet. When I run the system coupling, it throws an error which says 'negative volume detected.' I have tried decreasing the time step and that has not helped. I am using a time step of 0.001 sec and using remeshing method for dynamic mesh. The fluent user guide recommends using this method when the boundary displacements are large when compared to the local cell sizes. I have run the structural and fluent cases separately without any errors. This is the maximum deformation that is seen in the pipe.



I have applied the following pulsating pressure boundary condition in the structural setup.

Time(s) Pressure(MPa)

0. 0.

0.2 2.e-002

0.4 4.e-002

0.6 2.e-002

0.8 4.e-002

1. 2.e-002



The couple simulation fails at about 0.12 s.

I tried significantly scaling down the applied pulsating pressure such that the deformations are extremely small. The simulation ran only in this case but unfortunately this is not what I am looking for.

Could someone please help me troubleshoot the problem?

[mozkan26]

Hello,

Have you been able to resolve this issue? I'm facing a similar problem.

Many thanks.