# Neumann condition in stokes equation

**URL:** <https://community.freefem.org/t/neumann-condition-in-stokes-equation/2448>\
**Category:** General Discussion\
**Created:** [May 7, 2023, 12:06pm UTC](https://community.freefem.org/t/neumann-condition-in-stokes-equation/2448 "2023-05-07T12:06:48Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![Jamal](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/jamal/32/1527_2.png) [@Jamal](https://community.freefem.org/u/Jamal)\
**Post date:** [May 7, 2023, 12:06pm UTC](https://community.freefem.org/t/neumann-condition-in-stokes-equation/2448/1 "2023-05-07T12:06:48Z")

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Hello everyone;  
Can you please guide me on how to apply the Neumann boundary condition in the Stokes equation on \Gamma\_d?

\begin{equation}  
\begin{cases}-v \Delta u+\nabla p=0 & \text { in } \Omega \ \nabla \cdot u=0 & \text { in } \Omega \ u=U & \text { on } \Gamma\_d \ \sigma(u) \cdot n=F & \text { on } \Gamma\_d\end{cases}  
\end{equation}

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**Author:** ![frederichecht](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/frederichecht/32/15_2.png) [@frederichecht](https://community.freefem.org/u/frederichecht)\
**Post date:** [May 8, 2023, 8:26am UTC](https://community.freefem.org/t/neumann-condition-in-stokes-equation/2448/2 "2023-05-08T08:26:46Z")

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Some year ago , I write slide of BC Stokes problem.  
[BC-STOKES.pdf](https://community.freefem.org/uploads/short-url/p5xLXkSY1M6Drz3KbfwyQjOZZ8B.pdf) (216.7 KB)

with some examples;  
[Stokes-Pipe-Curve.edp](https://community.freefem.org/uploads/short-url/eHNXygj1DDM13kf2gYcIJS2a7uW.edp) (2.1 KB)

[Stokes-Pipe.edp](https://community.freefem.org/uploads/short-url/N8HMD506D7vouL6xu7FWRdKWAh.edp) (944 Bytes)