effect of Reynolds number

Discuss acquisition, use, and manipulation of airfoil data.

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Farshad.Golnari
Posts: 10
Joined: Sun Mar 26, 2017 11:29 am
Organization: Sharif University
Location: Iran Tehran

effect of Reynolds number

Postby Farshad.Golnari » Sat Apr 22, 2017 9:22 am

dear Jason
i have a general question about airfoils lift and drag coefficients. as i know, lift and drag coefficients are function of angle of attack and Reynolds number.usually airfoils lift and drag coefficients are computed in constant Reynolds number(for example ,lift and drag coefficients of airfoil S818 are computed in Reynolds number 4000000).the question that i want to ask is what Reynolds number must be selected for these calculations?

Jason.Jonkman
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Re: effect of Reynolds number

Postby Jason.Jonkman » Mon Apr 24, 2017 6:29 am

Dear Farshad,

Unfortunately, AeroDyn v15 within FAST v8 does not yet support interpolation of airfoil data based on Reynold’s number. If the airfoils you are using are strongly influenced by Reynold’s number, I would suggest finding the “expected” Reynold’s number at each radial station (based e.g. on omega cross radius) and choosing airfoil data there appropriate to that Reynold’s number.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov

Farshad.Golnari
Posts: 10
Joined: Sun Mar 26, 2017 11:29 am
Organization: Sharif University
Location: Iran Tehran

Re: effect of Reynolds number

Postby Farshad.Golnari » Mon Apr 24, 2017 11:18 pm

Dear Jason,
thank you very much for your brief answer. i wan to know,What is the error due to ignoring the effect of the Reynolds number in Aerodyn 15 and FAST simulation?
best regards

Jason.Jonkman
Posts: 3753
Joined: Thu Nov 03, 2005 4:38 pm
Location: Boulder, CO
Contact:

Re: effect of Reynolds number

Postby Jason.Jonkman » Tue Apr 25, 2017 6:18 am

Dear Farshad,

I can't answer your question in general. Some airfoils have coefficients that are strongly dependent on Reynold's number, while other airfoils have a weak dependence.

Best regards,
Jason Jonkman, Ph.D.
Senior Engineer | National Wind Technology Center (NWTC)

National Renewable Energy Laboratory (NREL)
15013 Denver West Parkway | Golden, CO 80401
+1 (303) 384 – 7026 | Fax: +1 (303) 384 – 6901
nwtc.nrel.gov


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