# Modal analysis using cylindrical coordinates

**URL:** https://community.freefem.org/t/modal-analysis-using-cylindrical-coordinates/2366
**Category:** General Discussion
**Created:** [March 30, 2023, 12:53pm UTC](https://community.freefem.org/t/modal-analysis-using-cylindrical-coordinates/2366 "2023-03-30T12:53:01Z")
**Posts on this page:** 1
**Showing post:** 3

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### Author: ![cmd](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/cmd/32/67_2.png) [@cmd](https://community.freefem.org/u/cmd)
#### Post date: [March 31, 2023, 6:58am UTC](https://community.freefem.org/t/modal-analysis-using-cylindrical-coordinates/2366/3 "2023-03-31T06:58:50Z")

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If the structure is axisymmetric and your problem is linear, I would suggest you keep your problem in a 2D framework and expand along theta in a Fourier series of integer azimuthal wavenumbers.

Otherwise, you can try what @frederichecht suggests here: [Cylindrical coordinate for flow simulation](https://community.freefem.org/t/cylindrical-coordinate-for-flow-simulation/1941)

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