# Poiseuille profil, Stokes , Uzawa

**URL:** <https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197>\
**Category:** General Discussion\
**Created:** [December 13, 2019, 3:18pm UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197 "2019-12-13T15:18:43Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![TheodoraVa3](https://avatars.discourse-cdn.com/v4/letter/t/8e7dd6/32.png) [@TheodoraVa3](https://community.freefem.org/u/TheodoraVa3)\
**Post date:** [December 13, 2019, 3:18pm UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197/1 "2019-12-13T15:18:43Z")

</div>

Hi everyone,

I am new to this amazing world of FreeFem users and I am having some issues with my work on a Poiseuille profil for Stokes equations with the Uzawa method.  
My results are totally wrong but I don’t see what I have to change.  
Could you give me some advice or recommandations to improve my work.

> **[uzawa\_poiseuille.edp](https://drive.google.com/file/d/1T1T8ogmRTG1Rx-8CfJLmNUO6RYBDX1S7/view?usp=sharing)**
>
> Google Drive file.

Thanks for your time.

---

<div class="post-metadata">

**Author:** ![prj](https://avatars.discourse-cdn.com/v4/letter/p/ecae2f/32.png) [@prj](https://community.freefem.org/u/prj)\
**Post date:** [December 13, 2019, 6:12pm UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197/2 "2019-12-13T18:12:58Z")

</div>

If you are looking for something much more efficient than Uzawa method, you can look at PETSc examples, e.g., [stokes-fieldsplit-3d-PETSc.edp](https://github.com/FreeFem/FreeFem-sources/blob/develop/examples/hpddm/stokes-fieldsplit-3d-PETSc.edp), which also solves Stokes equations with a Poiseuille inflow.

---

<div class="post-metadata">

**Author:** ![TheodoraVa3](https://avatars.discourse-cdn.com/v4/letter/t/8e7dd6/32.png) [@TheodoraVa3](https://community.freefem.org/u/TheodoraVa3)\
**Post date:** [December 13, 2019, 9:02pm UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197/3 "2019-12-13T21:02:55Z")

</div>

Thanks for you answer, I have already solved the problem with another method, but i have to compare it with the Uzawa one (that’s the work I am ask to do). I think my problem is maybe link to how I apply boundaries conditions and the labels identification.

---

<div class="post-metadata">

**Author:** ![simon.garnotel](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/simon.garnotel/32/11_2.png) [@simon.garnotel](https://community.freefem.org/u/simon.garnotel)\
**Post date:** [December 15, 2019, 8:48am UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197/4 "2019-12-15T08:48:04Z")

</div>

Have a look on my [PhD dissertation](http://theses.fr/2016AMIE0031), there is a complete Uzawa algorithm in the appendix

---

<div class="post-metadata">

**Author:** ![emmawilson](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/emmawilson/32/2346_2.png) [@emmawilson](https://community.freefem.org/u/emmawilson)\
**Post date:** [May 25, 2024, 7:43am UTC](https://community.freefem.org/t/poiseuille-profil-stokes-uzawa/197/6 "2024-05-25T07:43:41Z")

</div>

Hello,  
I’d be happy to help you troubleshoot your code. You can follow these suggestions:

1. Check Boundary Conditions
2. Mesh Quality
3. Parameter Tuning
4. Initial Guess
5. Debugging Output
6. Comparison with Analytical Solution
7. Code Review  
You can also check this : [FreeFem-sources/examples/hpddm/stokes-fieldsplit-3d-PETSc.edp at develop](https://github.com/FreeFem/FreeFem-sources/blob/develop/examples/hpddm/stokes-fieldsplit-3d-PETSc.edp)[generative-ai](https://www.igmguru.com/machine-learning-ai/generative-ai-training/)

I hope this will help you.

Thanks