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-   -   Oscillating Airfoil Poor Results at High k (reduced frequency) (http://www.cfd-online.com/Forums/openfoam-solving/113078-oscillating-airfoil-poor-results-high-k-reduced-frequency.html)

dancfd February 11, 2013 23:24

Oscillating Airfoil Poor Results at High k (reduced frequency)
 
Hello all,

I am trying to simulate an oscillating 2D airfoil section, angle of attack = 5 +- 5 deg. I find that I can obtain results that match experimental data for Cl quite well at a reduced frequency of k = 0.01, but at k = 0.1, the results do not match very well at all. I have let the simulation run until each cycle produces the same results, but the results do not compare well to experiment.

Can anyone suggest what could improve the simulation results at higher reduced frequency? I am running simpleFoam with a timestep of 5e-5 s and maximum Courant number of about 1. I am "oscillating" the airfoil by using a static mesh and time-dependent boundary condition for U.

Thanks in advance,

Dan

Tarak April 24, 2013 13:39

Hii Daniel,

Have you tried using AMI for oscillating the airfoil?

dancfd April 24, 2013 20:52

Hello Tarak,

I have looked into AMI, however the options available for compressible solvers (sonicDyMFoam, rhoCentralDyMFoam) do not allow the same mesh motion algorithms as the incompressible solvers (pimpleDyMFoam), and therefore the solution shown by the mixer tutorial cannot be implemented. I have tried adapting rhoPimpleFoam and sonicDyMFoam to use the incompressible-style mesh motion algorithm, so far with little success. It remains unclear to me why the incompressible and compressible solvers would handle mesh motion so differently - when there is no reason to be different, why not remain the same?

Regards,

Dan

arashfluid November 4, 2013 09:32

pitching motion
 
Hi foamers,
I am working on FSI problem. I want to move an airfoil with plunging motion.I used NACA 0012 airfoil has a chord length of c=0.15m, that undergoes sinusoidal plunging motion with an angle of attack of the type α(t) = αmean+Δαsin (ωt) around an axis located at quarter of its chord length (0.25c) from the leading edge. I have chosen a sinusoidal motion same as that of the available experimental data, given by α=10°+15°sin(ωt).
How do I apply for this move?


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