WALL PRESSURE CORRELATIONS IN TURBULENT PIPE FLOW
NAVY UNDERWATER SOUND LAB NEW LONDON CT
Pagination or Media Count:
Certain properties of the pressure field induced by turbulent airflow at the wall of a cylindrical pipe were investigated over broad frequency bands and in octave frequency bands over a limited range of Reynolds numbers. The broad-band measurements indicate that the pressure field is convected downstream at approximately 0.7 of the centerline velocity. The ratio of the root- means-quare pressure to the dynamic pressure is approximately equal to 0.006 for the various Reynolds numbers. Longitudinal and lateral space correlations are also presented for a limited range of spatial separations. Data obtained in octave frequency bands indicate that the ratio of convection velocity to centerline velocity decreases as frequency increases, with the ratio varying from approximately unity to 0.64 for the frequency bands investigated. Longitudinal and lateral correlation data for various frequencies, spatial separations, and Reynolds numbers are shown to be functions of Strouhal number. Estimates of the longitudinal and lateral scales are given as functions of frequency for the various Reynolds numbers. These data indicate that the lateral scale is approximately equal to one half of the longitudinal scale.
- Fluid Mechanics