[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.

I created a cylinder around it so that the cylinder rotates and inturn the wing rotates. I created a cuboidal part that acts as a wind tunnel.

I gave a velocity of 2m/s and performed a transient CFD analysis and measured the lift after every time step.

I'm using the k-e, RNG, swirl dominated flow with scalable wall function.
The problem is I'm getting negative cl and inturn a negative lift force.
Can you please help me figure out why I'm getting a negative lift and how to make it positive?

I first created a boolean between the wing and the rotating wall and then a boolean (while preserving body) between the wind tunnel and the rotating wall.

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!

https://youtu.be/jM-M0eLhM_4