# Applying pressure as boundary condition

**URL:** https://community.freefem.org/t/applying-pressure-as-boundary-condition/1340
**Category:** General Discussion
**Created:** [November 19, 2021, 5:42pm UTC](https://community.freefem.org/t/applying-pressure-as-boundary-condition/1340 "2021-11-19T17:42:14Z")
**Posts on this page:** 1
**Page:** 1

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### Author: ![distractor](https://avatars.discourse-cdn.com/v4/letter/d/57b2e6/32.png) [@distractor](https://community.freefem.org/u/distractor)
#### Post date: [November 19, 2021, 5:42pm UTC](https://community.freefem.org/t/applying-pressure-as-boundary-condition/1340/1 "2021-11-19T17:42:14Z")

</div>

Hi,

Let’s take the official elasticity example from [here](https://doc.freefem.org/tutorials/elasticity.html). Let’s remove the body force f and add another boundary condition at the right side (`label = 2`). This boundary condition is a pressure `p` that will elongate the beam in `x` direction.

Is this the right way to assign a pressure boundary condition to the right side? I would say it is not, however, I can’t figure out what is.

```auto
25 solve lame([u, v], [uu, vv])
26 = int2d(Th)(
27 lambda * div(u, v) * div(uu, vv)
28 + 2.*mu * ( epsilon(u,v)' * epsilon(uu,vv) )
29 )
30 - int1d(Th, 2)(
31 p*uu
32 )
33 + on(4, u=0, v=0)
34 ;

```