Modal analysis of actively controlled flow past a backward facing ramp

This paper aims at investigating the main coherent structures of the flow past a backward facing ramp. The flow has been experimentally studied through Stereo-PIV, hot-wire measurements and unsteady pressure measurements by using Kulite probes flush-mounted on the slant. The spectral proper orthogonal decomposition (SPOD) is applied to identify the main spatial and dynamic features of the flow, in controlled and uncontrolled conditions. This analysis is part of a wider activity that aims at investigating the effectiveness of the active control of separated flows, with periodic pulsed jets. The results obtained through the SPOD analysis are compared with findings arising from the spectra of hot-wire measurements and the correlation approach.