MEASUREMENTS OF WALL PRESSURE FIELD AT SURFACE OF A SMOOTH-WALLED PIPE CONTAINING TURBULENT WATER FLOW

An experimental study has been made of the statistical properties of the wall pressure field generated by the passage of fully-developed turbulent water flow in a smooth-walled pipe. A pump-driven water flow facility capable of producing Reynolds numbers of 2 × 106 in a 20 ft long, 6 in. diameter pipe test section was designed and constructed for this investigation. Noise reduction techniques were employed to minimize the transmission of pump noise to the test section. Wall-mounted miniature pressure transducers were fabricated to record the pressure fluctuations in the longitudinal and circumferential directions of the pipe wall. The statistical properties of the wall pressure field determined from these recordings included the power spectral density, space-time correlations, and convection speeds embracing both broad and narrow (third-octave) frequency bands. It was found that the wall pressure field data exhibit many properties similar to those reported from independent studies in subsonic boundary layer and pipe flows. The results indicate that the frequencies of the pressure fluctuations scale with the flow speed. It was also found that the narrow-band filtered space correlation functions depend not only on the Strouhal number but also vary with the frequency. © 1969.