Lift Hysteresis problem in Oscillating Airfoil

February 6, 2008, 16:01

I have run a simulation for Alpha(t)=10+2sinwt. I got Cd hysteresis loop as the same as experimental but I got the Opposite loop for Cl. I am getting higher lift during the downstroke but it should be lower than that of upstroke.

Can anybody help me regarding this problem.

N.B. Airfoil is NACA0012, M=0.3, Re=0.54 Million.

February 6, 2008, 17:16

Hi,

Obviously you need to validate your model. Check mesh, timestep, convergence, physics, etc etc. It all needs to be correct to get an accurate answer.

Glenn Horrocks

churchill · March 28, 2012, 10:34

Quote:

Originally Posted by Farid
;85907

I have run a simulation for Alpha(t)=10+2sinwt. I got Cd hysteresis loop as the same as experimental but I got the Opposite loop for Cl. I am getting higher lift during the downstroke but it should be lower than that of upstroke.

Can anybody help me regarding this problem.

N.B. Airfoil is NACA0012, M=0.3, Re=0.54 Million.

hello Farid, will you please tell me how to set the simulation in Fluent for hysteresis problem?I got no idea about the settings, such as the UDF,solution,boundary condition.
Thank you a lot!

ghorrocks · March 29, 2012, 06:52

You are posting on the wrong forum. You are looking for the Fluent forum, this is the CFX forum.

February 6, 2008, 16:01	Lift Hysteresis problem in Oscillating Airfoil	#1
Farid Guest Posts: n/a	I have run a simulation for Alpha(t)=10+2sinwt. I got Cd hysteresis loop as the same as experimental but I got the Opposite loop for Cl. I am getting higher lift during the downstroke but it should be lower than that of upstroke. Can anybody help me regarding this problem. N.B. Airfoil is NACA0012, M=0.3, Re=0.54 Million.

February 6, 2008, 17:16	Re: Lift Hysteresis problem in Oscillating Airfoil	#2
Glenn Horrocks Guest Posts: n/a	Hi, Obviously you need to validate your model. Check mesh, timestep, convergence, physics, etc etc. It all needs to be correct to get an accurate answer. Glenn Horrocks

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March 29, 2012, 06:52		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,844 Rep Power: 144	You are posting on the wrong forum. You are looking for the Fluent forum, this is the CFX forum.