# Polar Velocity components

**URL:** https://discourse.paraview.org/t/polar-velocity-components/13786
**Category:** ParaView Support
**Tags:** python
**Created:** [January 24, 2024, 7:55am UTC](https://discourse.paraview.org/t/polar-velocity-components/13786 "2024-01-24T07:55:54Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![Mahmoud\_Hosny](https://discourse.paraview.org/user_avatar/discourse.paraview.org/mahmoud_hosny/32/12333_2.png) [@Mahmoud\_Hosny](https://discourse.paraview.org/u/Mahmoud_Hosny)
#### Post date: [January 24, 2024, 7:55am UTC](https://discourse.paraview.org/t/polar-velocity-components/13786/1 "2024-01-24T07:55:54Z")

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Hi, I have a cylindrical geometry and want to get the two velocity components in polar coordinates,  
V\_r & V\_theta.

How to do that?

---

<div class="post-metadata">

### Author: ![FEngineer](https://discourse.paraview.org/letter_avatar_proxy/v4/letter/f/5f8ce5/32.png) [@FEngineer](https://discourse.paraview.org/u/FEngineer)
#### Post date: [January 25, 2024, 9:48am UTC](https://discourse.paraview.org/t/polar-velocity-components/13786/2 "2024-01-25T09:48:57Z")

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You can use the Calculator filter for that. Try those formulas:

```auto
v_r=(x*v_x+y*v_y)/sqrt(x^2+y^2)
v_t=(x*v_y-y*v_x)/sqrt(x^2+y^2)

```

Of course, x and y are coordinates. They can be accessed from the Calculator.

And please upvote this feature request if you’d like to have a built-in filter that can do such a transformation: [Transforming results to user-defined (local) coordinate systems](https://discourse.paraview.org/t/transforming-results-to-user-defined-local-coordinate-systems/9387)