NACA 0012 2D - SA model - Drag overprediction

Panglos · March 27, 2019, 16:04

Hi everyone!

As the title suggests I am facing some problems while trying to simulate the flow around a NACA 0012 airfoil. Basically, I obtain drag coefficient values which are overestimated compared against the experiments.

I am using a Spalart-Allmaras model with nu_tilda = nu and nut/nu_tilda = 3. I tried different meshes, boundary conditions and numerical scheme by I always end up with some discrepancies. E.g. for the 0 angle of attach I obtain 1e-3 instead of 6e-4

Find at this link the setup for my case:
https://we.tl/t-10bcvAXo4n

Thank you in advance for your time.

mzzmrt · March 28, 2019, 10:40

It may be mesh or boundary condition related.

Could you try another meshing approach other than blockMesh? I strongly recommend Construct2D for this purpose.

sheaker · March 28, 2019, 12:55

Hello.

I think You need a transitional model like k-omega SST or gamma re theta.
In Spalart-Allmaras model flow is fully turbulent everywhere so drag coefficient is overestimated.

Please correct me if I am wrong.

Best regards,
Oskar

March 27, 2019, 16:04	NACA 0012 2D - SA model - Drag overprediction	#1
Panglos New Member Join Date: Sep 2015 Posts: 5 Rep Power: 10	Hi everyone! As the title suggests I am facing some problems while trying to simulate the flow around a NACA 0012 airfoil. Basically, I obtain drag coefficient values which are overestimated compared against the experiments. I am using a Spalart-Allmaras model with nu_tilda = nu and nut/nu_tilda = 3. I tried different meshes, boundary conditions and numerical scheme by I always end up with some discrepancies. E.g. for the 0 angle of attach I obtain 1e-3 instead of 6e-4 Find at this link the setup for my case: https://we.tl/t-10bcvAXo4n Thank you in advance for your time.

March 28, 2019, 12:55		#3
sheaker Senior Member Oskar Join Date: Nov 2015 Location: Poland Posts: 184 Rep Power: 10	Hello. I think You need a transitional model like k-omega SST or gamma re theta. In Spalart-Allmaras model flow is fully turbulent everywhere so drag coefficient is overestimated. Please correct me if I am wrong. Best regards, Oskar __________________ How to set two stroke engine with scavenging? Salome, sliding interface and "Zero length edge detected."

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Data for NACA 0012	Muntazir	Main CFD Forum	1	March 28, 2023 01:59
Induced drag, pressure drag, viscous drag.	aleix.de.toro	FLUENT	2	August 24, 2015 18:00
Negative Drag coefficient naca 0012 airfoil using fluent 15	lucasvfc	FLUENT	8	March 13, 2015 14:43
NACA 0012 validation Drag problems	leo_NM	FLUENT	7	August 8, 2014 14:18
drag overprediction	Yuri	Siemens	10	August 29, 2001 05:53

March 28, 2019, 10:40		#2
mzzmrt Senior Member Join Date: Mar 2014 Posts: 112 Rep Power: 12	It may be mesh or boundary condition related. Could you try another meshing approach other than blockMesh? I strongly recommend Construct2D for this purpose.