Learning Forum

[Nishanth]

Hello,

I've been trying to perform a CFD analysis of a flapping wing. Please view the attached images.

I have taken a flat rectangular wing inclined at an angle of 45d to the wingspan-axis and 15d to the fuselage-axis.

[YasserSelima]

when you are creating the lift report, what is the direction of lift? you will see x, y and z values n

[Nishanth]

Hey, I'm measuring lift at (x, y,z = 0,0,1). Where z is the vertical axis. nThe sign convention is also proper, The Z-axis line on Ansys faces upwards. n

[YasserSelima]

did you complete 360 degrees rotation?n

[Nishanth]

did you complete 360 degrees rotation?/forum/discussion/comment/103352#Comment_103352

No, Just 60 degrees downwards and 60 degrees upwards which will send it back to the original position. Mimicking flapping motion.n

[Nishanth]

UPDATE: The lift is positive when I do a static analysis at -15d and 60d dihedral. But as soon as a start the mesh motion the lift goes negative! nPlease help. n

[YasserSelima]

I think it will be -ve for 180 degrees and positive in the other 180 degree. This what I expect from your geometry. Try moving it 360 degreesn

[Nishanth]

I think it will be -ve for 180 degrees and positive in the other 180 degree. This what I expect from your geometry. Try moving it 360 degrees/forum/discussion/comment/103368#Comment_103368

Not working. nI think the problem is with the boolean. Because when I check streamlines, I can hardly see them go in the rotating wall. The values are negative but are nearly zero.nCan you please check if the way I have performed my boolean is correct? Because when I try to hide the face I need to hide the face of the rotating wall twice. n

[YasserSelima]

If you have a wall and wall shadow, this means you identified the flapping wing as solid. This is not required if you do not have FSI. You can just make it as a gab. nI would suggest decreasing the duct dimensions trying to force the flow to enter your moving frame. Another solution is to use UDF to rotate the wing instead of the MRF. But this will require some work from you.n

[DrAmine]

What kind of boundary separates the rotating zone from non rotatingn