Flow over a cavity inconsistent
 

Hi all,

I have been running through Fluent simulations for flow over a cavity to study self-oscillating cavity flows. So far with cavities that have a cavity opening length (L) less than that of the cavity depth (D) I get results consistent with available experimental data and exhibit very periodic oscillations. However, simulations that have a L/D>1 exhibit very random time histories inconsistent with experiment.

I am using DES SST k-omega solver, y+=1, second order settings, time step is 0.008 for 100-150 seconds, core flow is around 2cm/s. Most everything else is default.

From literature there is a difference in flow regime for deep cavity flow (L/D<1) and shallow cavity flow (L/D>1). Deep cavities act like resonators with the shear layer acting as a forcing mechanism. Shallow cavities oscillate due to propagating disturbances amplified through the shear layer.

Any ideas for how I can try and capture this shallow cavity flow regime behavior?

Thanks,
Stephen