3d aerofoil cant stall at higher AOA

Louiskhoo · June 14, 2019, 02:22

Guys, recently i am conducting a project which is to simulate a 3D airfoil. However, my lift force cannot stall at higher AOA. The dimension of my airfoil is 127mm chord, 245mm span. Air density 1.225kg/m^3, dynamic viscosity is 1.789e-5. From here, my reynolds number is fully turbulent. Boundary condition for inlet is 133m/s. And also, what kind of model should i use? K epsilon? K omega sst? Or..... Next, for the reference value in setup. Shuld i compute from inlet? Cus some of the video tutorial does not include tht. I nid help, is very urgent.
Thanks
Louiskhoo

jeytsav · June 14, 2019, 20:17

Hello,

What airfoil section are you using? Is it a NACA series?

At which AOA do you expect it to stall? Please keep in mind that 3D wings reach a stall at higher AOAs than their equivalent 2D airfoil. There are analytical formulas which can give a good estimation of the Lift coefficient of a 3D wing available in the literature.

Best,
Ioannis

Louiskhoo · June 17, 2019, 23:45

I am using NACA 4412. In general, the airfoil should hae stalled at the angle of 16 to 20 degree. However, the force keep increasing as the AOA increased. Is it true that 2d simulation can easily obtain the stall angle compared to 3d? Can you kindly provide me any article about that so that i could convince my invigilator. Thanks a lot for your help.
Louis.

June 14, 2019, 02:22	3d aerofoil cant stall at higher AOA	#1
Louiskhoo New Member Anonymous Join Date: Jun 2019 Posts: 2 Rep Power: 0	Guys, recently i am conducting a project which is to simulate a 3D airfoil. However, my lift force cannot stall at higher AOA. The dimension of my airfoil is 127mm chord, 245mm span. Air density 1.225kg/m^3, dynamic viscosity is 1.789e-5. From here, my reynolds number is fully turbulent. Boundary condition for inlet is 133m/s. And also, what kind of model should i use? K epsilon? K omega sst? Or..... Next, for the reference value in setup. Shuld i compute from inlet? Cus some of the video tutorial does not include tht. I nid help, is very urgent. Thanks Louiskhoo

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June 14, 2019, 20:17		#2
jeytsav Member jey Join Date: Nov 2016 Location: Greece Posts: 30 Rep Power: 9	Hello, What airfoil section are you using? Is it a NACA series? At which AOA do you expect it to stall? Please keep in mind that 3D wings reach a stall at higher AOAs than their equivalent 2D airfoil. There are analytical formulas which can give a good estimation of the Lift coefficient of a 3D wing available in the literature. Best, Ioannis

June 17, 2019, 23:45		#3
Louiskhoo New Member Anonymous Join Date: Jun 2019 Posts: 2 Rep Power: 0	I am using NACA 4412. In general, the airfoil should hae stalled at the angle of 16 to 20 degree. However, the force keep increasing as the AOA increased. Is it true that 2d simulation can easily obtain the stall angle compared to 3d? Can you kindly provide me any article about that so that i could convince my invigilator. Thanks a lot for your help. Louis.