Calculating eigenvalues for the Stokes equations in 3D

Hello!
In my project I have to calculate eigenvalues for the three dimensional Stokes equations with Dirichlet boundary conditions. I would like to use FEniCS for this purpose, but I’m not quite sure how to do it correctly. I would be grateful if anyone could share a source code for solving this eigenvalue problem.
Thank you very much!
Alex

https://fenicsproject.org/docs/dolfin/latest/python/demos/eigenvalue/demo_eigenvalue.py.html

Just need to remplace the weak form !

Thibaut, thank you! If I understood you correctly, all I need to do is to change the definition of the bilinear form in this example. But how should I add the divergence-free condition necessary to define the Stokes operator?

There are numerous formulations for Stokes flow, but the following demo

https://fenicsproject.org/docs/dolfin/latest/python/demos/stokes-iterative/demo_stokes-iterative.py.html

provides the bilinear form for using Galerkin’s method with an inf-sup stable pressure–velocity pair (e.g., the Taylor–Hood element from the demo).

David, thank you very much for your help!