Assessment of the organized turbulent separated and reattaching flow by local forcing was made by measuring wall pressure fluctuations. Multi-arrayed microphones were installed on the surface to measure the simultaneous spatial and temporal wall pressure fluctuations. The local forcing at the separation edge was given to the separated flow over a backward-facing step through a thin slit. The separated and reattaching flow was most organized at the effective forcing frequency. The organized flow structure by local forcing was diagnosed by analyzing the information of wall pressure fluctuations. Several characteristics of wall pressure fluctuations were obtained : wall pressure fluctuation coefficients, wall pressure spectrum, wavenumber-frequency spectrum, coherence, cross-correlation, and multi-resolution autocorrelations of pressure fluctuations using the maximum overlap discrete wavelet transform (MODWT) and continuous wavelet transform (CWT). The amalgamation process of vortices were observed, which gives the maximum reduction of the reattachment length. The enhancements of the flapping motion, streamwise and spanwise dispersions of vortical structures were examined by the wall pressure fluctuations.
