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.