# Simulation of a pure-pitching and pure-plunging airfoil

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 September 1, 2021, 06:40 Simulation of a pure-pitching and pure-plunging airfoil #1 New Member   Join Date: Jun 2021 Posts: 8 Rep Power: 4 Hi, I would like to simulate the unsteady aerodynamics of two different and decoupled airfoil motions: firstly the pure plunging motion and secondly the pure pitching motion. Is there a way to specify time-varying inlet velocities (one for pure-plunge and another one for pure-pitch) so that the interaction fluid-airfoil represents the desired motion? Thanks in advice!

 September 1, 2021, 10:49 #2 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,672 Rep Power: 65 In general you can. But it's even more straightforward than that. You can just specify the pitching and plunging motion to the airfoil walls even without any mesh motion.

September 1, 2021, 10:51
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 Originally Posted by LuckyTran In general you can. But it's even more straightforward than that. You can just specify the pitching and plunging motion to the airfoil walls even without any mesh motion.

Can you explain to me how I can do that?

 September 1, 2021, 11:47 #4 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,672 Rep Power: 65 Well can you describe your pitching/plunging airfoil motion first? I gather from your other post that you need someone else to do all the work from A to Z for you and I'm not the one to do that.

September 1, 2021, 12:01
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 Originally Posted by LuckyTran Well can you describe your pitching/plunging airfoil motion first? I gather from your other post that you need someone else to do all the work from A to Z for you and I'm not the one to do that.
Yes, I know the equations that are required to describe the change in angle of attack (for the pitching motion) and the change of the y-coordinate (for the plunging motion). However I do not know how these motions to the airfoil walls. Do you know the procedure?

 September 1, 2021, 12:18 #6 Senior Member   Lucky Join Date: Apr 2011 Location: Orlando, FL USA Posts: 5,672 Rep Power: 65 So first you open up Star obviously. Then you scroll all the way down in the tree to find tools. Then you go to Field Functions and create a bunch of Field Functions as you need. Or you go to motion and create a morpher. You do the mechanical work of typing in all the syntax to properly write down your equations into Star. Then you go back to regions, find your velocity inlet. Go to physics values. Go to velocity magnitude and change it from constant to field function. Link it to field function you created. But since velocity magnitude and direction is probably not how you want to do this in the first place... You might need to go to physics conditions before this and change the velocity specification from magnitude & direction to components.

 Tags airfoil, pitch, plunge, unsteady, velocity inlet