# Non linear time dependent problem

**URL:** <https://community.freefem.org/t/non-linear-time-dependent-problem/856>\
**Category:** General Discussion\
**Created:** [March 16, 2021, 6:39pm UTC](https://community.freefem.org/t/non-linear-time-dependent-problem/856 "2021-03-16T18:39:59Z")\
**Posts on this page:** 1\
**Showing post:** 2

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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:** [March 17, 2021, 4:21pm UTC](https://community.freefem.org/t/non-linear-time-dependent-problem/856/2 "2021-03-17T16:21:58Z")

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During the freefem days and all during teaching sessions, I solve of Boussinessq Equation  
(Inccompressible Navier Stokes with temperature) to see Rayleigh-Bernard instability.

The Non linear Part is done with Fixe-Point and Newton iteration method,  
And I use BDF 3 schema for the time integration.

[Rayleigh-Benard-time.edp](https://community.freefem.org/uploads/short-url/7wQywbkMyb4Wwdsve9S4CalfMZa.edp) (3.9 KB)

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