Learning Forum

[Silvia Picchi]

Hi all,

I am currently working on a university project which requires me to study the noise produced by a blunt airfoil, with and without a splitter plate, with FH-W equations in ANSYS Fluent.
I have a 2D airfoil (chord: 1m) with velocity inlet = 15 m/s (direction x) and pressure outlet as boundary conditions.  
After solving 800 timesteps of my simulation (dt = 0.00333s) without the acoustic model (to obtain correct static pressure values, Cl, Cd), I turn on the acoustic model and solve and extra 1600 timesteps and then ask the software to give me the signal data as FFT (Hz-SPL plot). The results I get for all my receivers, however, are significantly different from what I expect from the literature on airfoil noise, but I can't find the error. The mesh has good quality, and I do not receive any kind of warning.

I am putting here a few screenshot of the case set up.

If anyone has any suggestions, I will gladly accept your help.

 

 

Results from the receivers (1st row at a distance of 2m from the blunt edge, 2nd row at a distance of 20m):

[Federico]

Hello Silvia, 

what are you using for the source of your noise?

Also, you mentioned that your mesh is of good quality. How does that relate to your acoustic Courant number with the chosen time step?

You also need to take into account the target frequency range and make sure you have enough samples to resolve this range.