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How to compute Reynolds number from information in inv_NACA0012.cfg ?

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Old   April 7, 2021, 13:55
Default How to compute Reynolds number from information in inv_NACA0012.cfg ?
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Harry Kim
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I'm struggling about calculating Reynolds number based on the flow conditions given in "inv_NACA0012.cfg" file. (txt file attached)

According to the free-stream definition in the .cfg file,
Mach number = 0.8 and Freestream Temperature = 273.15

I could calculate Reynolds number using

Re = (Freestream vel* Length of Airfoil)/Kinematic viscosity
= (Mach number*Speed of Sound @ 273K * Length of Airfoil)/Kinematic vis

How to know "Length of the Airfoil" to calculate Free-stream Reynolds Number based on information in the .cfg file?

If I have something wrong for Re calculation, please correct me.

FYI, this is the simplest test case for SU2 in the QuickStart tutorial.

Thanks in advance!
Attached Files
File Type: txt inv_NACA0012.txt (14.0 KB, 3 views)
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Old   April 9, 2021, 00:35
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Amit
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You need not input the Reynolds number for inviscid flow calculations. Adequate information is supplied in the file you have attached (M, P, T).

Also reference length is mentioned here in file for this case as -
REF_LENGTH= 1.0.

Anyways, you can work out Reynolds number as -

Re=Rho*V*Lref/mu

Get Rho from P, T. Obtain V=Mach*sqrt(Gamma*R*T), Lref is specified and mu can be computed from Sutherland's formula.
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Old   April 9, 2021, 00:53
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Quote:
Originally Posted by aero_amit View Post
You need not input the Reynolds number for inviscid flow calculations. Adequate information is supplied in the file you have attached (M, P, T).

Also reference length is mentioned here in file for this case as -
REF_LENGTH= 1.0.

Anyways, you can work out Reynolds number as -

Re=Rho*V*Lref/mu

Get Rho from P, T. Obtain V=Mach*sqrt(Gamma*R*T), Lref is specified and mu can be computed from Sutherland's formula.
Oh, you are right. Reynolds number in inviscid flow is theoretically infinite. I was just stupid being confused with viscous flow. Thanks for reminding me that!
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