# Question about Reynolds number

**URL:** <https://forums.nlr.gov/t/question-about-reynolds-number/294>\
**Category:** Computer-Aided Engineering Software Tools\
**Created:** [October 14, 2010, 9:23am UTC](https://forums.nlr.gov/t/question-about-reynolds-number/294 "2010-10-14T09:23:23Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Wei.Ni](https://avatars.discourse-cdn.com/v4/letter/w/3da27b/32.png) [@Wei.Ni](https://forums.nlr.gov/u/Wei.Ni)\
**Post date:** [October 14, 2010, 9:23am UTC](https://forums.nlr.gov/t/question-about-reynolds-number/294/1 "2010-10-14T09:23:23Z")

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Hello, everyone,

I have a question about Reynolds number for BEM method used by WT\_Perf/Aerodyn/FAST.  
For variable speed wind turbines the rotor speed depends on wind speed, this will lead to variable Reynolds number for the blade element during simulation. When preparing the airfoil characteristics, I always input Cl/Cd/Cm value for a fixed Reynold’s number. I wonder is it possible that I prepare several Cl/Cd/Cm values for different Reynolds number in airfoil file and let NREL codes do interpretation during simulation?

Thanks a lot!

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**Author:** ![Marshall.Buhl](https://avatars.discourse-cdn.com/v4/letter/m/f14d63/32.png) [@Marshall.Buhl](https://forums.nlr.gov/u/Marshall.Buhl)\
**Post date:** [October 14, 2010, 9:08pm UTC](https://forums.nlr.gov/t/question-about-reynolds-number/294/2 "2010-10-14T21:08:20Z")

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Yes. Both AeroDyn and WT\_Perf support multiple Reynolds numbers. Please see the user’s guides for the two programs.

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**Author:** ![Wei.Ni](https://avatars.discourse-cdn.com/v4/letter/w/3da27b/32.png) [@Wei.Ni](https://forums.nlr.gov/u/Wei.Ni)\
**Post date:** [October 15, 2010, 7:11am UTC](https://forums.nlr.gov/t/question-about-reynolds-number/294/3 "2010-10-15T07:11:06Z")

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Thank you very much! I will read the users’ manual carefully.