Experimental Investigation Of Shock Induced Panel Flutter With Simultaneous Use Of DIC And PIV

In this experimental study, both classical and shock induced supersonic panel flutter are investigated at a freestream Mach number of 2, using a combination of planar particle image velocimetry (PIV) and stereographic digital image correlation (DIC) to obtain simultaneous full-field structural displacement and flow velocity measurements. Highspeed cameras are employed to obtain a time-resolved description of the panel motion and of the flow dynamics. In order to prevent interference between the PIV and DIC systems, an optical isolation is implemented using fluorescent paint, dedicated light sources, and camera lens filters. For the shock induced case, the effect of the panel motion 

on the SWBLI behavior is assessed, by comparing it with the SWBLI on a rigid wall. The results show that panel oscillations occur with an amplitude of ten times the panel thickness. The dominant frequencies observed in the panel oscillation (424 Hz and 1354 Hz) match the main spectral content of the reflected shockwave position. In absence of shock impingement, the oscillation amplitude is on the order of the panel thickness, while the dominant frequency contribution is at 730 Hz. The fluid-structure coupling is studied by identifying the flow regions of maximum correlation between the panel displacement and the flow velocity fluctuations. In presence of shock impingement the results obtained proved that the inviscid flow region upstream of the SWBLI is perfectly in phase with the panel oscillation, while the downstream region has a delay of one quarter of the flutter cycle. Instead, no delay is observed for the configuration in absence of shockwave impingement.