# How to configure Sutherland's Law

**URL:** <https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701>\
**Category:** Cases\
**Tags:** config, compressible\
**Created:** [5 October 2022 09:00 UTC](https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701 "2022-10-05T09:00:41Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![YoonSuKyung](https://avatars.discourse-cdn.com/v4/letter/y/5e9695/32.png) [@YoonSuKyung](https://pyfr.discourse.group/u/YoonSuKyung)\
**Post date:** [5 October 2022 09:00 UTC](https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701/1 "2022-10-05T09:00:41Z")

</div>

How should variables related to sutherland’s law(mu and cpTref, cpTs) be defined to use normalized values(P=1, rho=1, u=1 ,)?  
Does the temperature not have a unit?

---

<div class="post-metadata">

**Author:** ![WillT](https://avatars.discourse-cdn.com/v4/letter/w/bc79bd/32.png) [@WillT](https://pyfr.discourse.group/u/WillT)\
**Post date:** [5 April 2023 08:48 UTC](https://pyfr.discourse.group/t/how-to-configure-sutherlands-law/701/2 "2023-04-05T08:48:10Z")

</div>

Sorry, this post seems to have slipped under the radar, PyFR doesn’t use units, but you are free to impose them on your solution as you like. As such if you want to use Sutherland’s law, you will probably need to do this, or make sure that Sutherlands law gives the correct values over the expected range of temperatures in your case.