MEASUREMENTS OF THE FLUCTUATING PRESSURE AT THE WALL BENEATH A THICK TURBULENT BOUNDARY LAYER
Abstract
Measurements of the turbulent pressure field at the wall beneath a thick (5-inch) turbulent boundary layer produced by natural transition on a smooth surface are reported. The data include the mean-square-pressure, power spectrum of the pressure, space-time correlation of the pressure parallel to the stream, and spatial correlation of the pressure transverse to the stream. The root-mean-square wall pressure was 2.19 times the wall shear stress. The power spectra of the pressure were found to scale with the free-stream speed and the boundary-layerdisplacement thickness. A few tests with a rough surface showed that the increase in rootmean-square wall pressure was greater than the increase in wall shear stress. The space-time correlation measurements parallel to the stream direction exhibit maxima at certain time delays corresponding to the convection of pressureproducing eddies at speeds varying from 0.56 to 0.83 times the stream speed. Both the transverse and the longitudinal scale of the pressure fluctuations were of the order of the boundarylayer-displacement thickness. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Apr 01, 1962
- Accession Number
- AD0274973
Entities
People
- C.e. Wooldridge
- W.w. Willmarth
Organizations
- University of Michigan