Scalar-image based decomposition technique for cavitating flows.

Abstract: A cross-wavelet transform (XWT) was used to elucidate the shedding modes of cavitating vortices in the wake of a nominally two-dimensional bluff body. The XWT was applied to all pixel locations in a high-speed video of the vortex street with the reference signal provided by a pressure tap in the aft-end of the bluff body. The spatial topology of the fundamental mode shape was shown to be nominally two-dimensional spanwise vortices, though these are not linear. The spacing of the vortices was extracted. This technique allows the description of a large data set with reduced dimensionality. Calculating the modes with a relative phase instead of absolute phase allows for simpler temporal analysis. Keywords: Cavitation, modal decomposition, vortices