Learning Forum

[thvasileiou]

Hi,

I am interested in simulating a pitching (NACA) 2D foil using Ansys Fluent. The foil rotates periodically between -5 and 5 degrees about its center of mass, and it is placed in a free stream velocity, as shown in the attached image. I am interested in performing an unsteady simulation on a body-fitted reference frame that follows the rotation of the foil. The mesh in this case will be static, but the fictitious forces terms due to the non inertial frame should be included in the fluid dynamic equations.

1) Is this simulation setup possible with Fluent? Are there any resources on the subject?
2) Going a step further: Would it be possible to assume that the fluid around the foil is initially stationary and that the foil is free to translate along the x and y directions? Namely simulate a self-propelled pitching 2D foil on a non-inertial frame?

Thank you in advance,
Thomas

[Rob]

NACA airfoils are covered in some of the tutorials, click on Help in Fluent. 

Mesh motion is quite computer & time expensive, but have a look at overset for what you want. However, for your initial work I'd also look at boundary conditions: profiles and expressions. Why move the mesh if you can move the flow? 

[thvasileiou]

Hi Rob,

Thanks for you answer. Moving the flow is actually what I have in mind, I would like to avoid mesh motion all together. Your suggestions regarding the boundary conditions is towards this direction, but I do not know how to implement the source terms in the fluid dynamic equations for the four fictitious forces (Coriolis force, the centrifugal force, the Euler force, and the rectilinear acceleration), since the frame is non-inertial (there is both rotation and acceleration). 

Do you have any suggestions?

Best,

Thomas