Scaling of turbulent wall pressure fluctuations downstream of a rearward facing step

The turbulent boundary layer that forms downstream of a surface discontinui ty is locally inhomogeneous. Here, we consider the boundary layer that occu rs downstream of a rearward facing step discontinuity on a flat plate that is exposed to a zero incidence, uniform subsonic flow. The wall pressure "p oint" spectra are measured by small, flush-mounted pressure transducers loc ated at various locations downstream of the step. A new form of the non dim ensional point wall pressure auto-frequency spectrum is proposed that inclu des the statistical variations of the reattachment location. This form is s hown to collapse quite well all of the spectra measured slightly upstream, within, and downstream of the flow reattachment location. (C) 1999 Acoustic al Society of America.