Extracting WSS for FSI simulation

[marisa bazzi]

Hey,

I am running a FSI simulation for a mouse-aorta, and when open the results on ParaView there is only stress option, which I am assuming it is Von Misses stress (or something on those lines), however I would like to be able to extract the WSS in the inner wall. How can I do it?

Best,
Marisa

[Vijay Vedula]

Hi Marisa,

For FSI simulations, quantities that are written to a vtu file by default include velocity, pressure, displacement and von Mises stress. All other output variables need to be defined by the user in the input file. These include WSS, Vorticity, Vortex (lamda_ci criterion), Traction, Divergence (of velocity), Viscosity (non-Newtonian), Stress (Cauchy stress tensor), Deformation_gradient, Jacobian, Fiber_direction and Fiber_alignment.

Thanks,
Vijay

[Vijay Vedula]

Here is an example of providing outputs:

Code: Select all

   Output: Spatial {
      Displacement: t
      Velocity: t
      Pressure: t
      WSS: t
      Stress: t
      VonMises_stress: t
   }

   Output: Alias {
      Displacement: FS_Displacement
   }

Note that both the outputs have to be within `Add equation' identifier in your input file.

In the first `Output: Spatial', the variables are written to vtu file. I have included both default ones and some additional quantities of interest.

In the second `Output: Alias', I want to rename `Displacement' variable as `FS_Displacement' to distinguish it from mesh displacement. Note that for FSI, a Displacement is written to file after solving the mesh equation. In the solid domain, both the quantities are exact, however, in the fluid domain you would be more interested in mesh displacement and not in FS_Displacement, where the latter is an integral of the velocity field. If these two quantities are named alike, Paraview will only render one of them while plotting.