# Eigenvalue problem for the Navier-Stokes equations

**URL:** <https://community.freefem.org/t/eigenvalue-problem-for-the-navier-stokes-equations/254>\
**Category:** General Discussion\
**Created:** [February 16, 2020, 8:08am UTC](https://community.freefem.org/t/eigenvalue-problem-for-the-navier-stokes-equations/254 "2020-02-16T08:08:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![AntonioGarcia](https://avatars.discourse-cdn.com/v4/letter/a/d78d45/32.png) [@AntonioGarcia](https://community.freefem.org/u/AntonioGarcia)\
**Post date:** [February 16, 2020, 8:08am UTC](https://community.freefem.org/t/eigenvalue-problem-for-the-navier-stokes-equations/254/1 "2020-02-16T08:08:48Z")

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Hi, I´m trying to solve the eigenvalue problem for the Navier-Stokes equations in a 2D configuration.

I’ve tried the method explained in the FreeFem manual but i haven’t find a way to adapt it to a problem with more than one function. Also, the problem has the peculiarity that pressure isn’t time dependent so the matrices have a special shape. I couldn’t find any example for this.

If someone knew how to solve it or knows an example where this problem is treated, it would be very helpful.

Thanks in advance

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**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [February 16, 2020, 9:12am UTC](https://community.freefem.org/t/eigenvalue-problem-for-the-navier-stokes-equations/254/2 "2020-02-16T09:12:33Z")

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You can have a look at the code (and paper) in the following [repository](https://github.com/prj-/moulin2019al), especially the file `Eigensolver.edp`. It’s in 3D, but should be easily adapted to 2D (in fact I need to do that for an upcoming FreeFEM tutorial). Let me know if you have some specific questions.