Accession Number : ADA324255

Title :   Wall Pressure Signatures of Organized Turbulent Motions.

Descriptive Note : Final rept.,

Corporate Author : CATHOLIC UNIV OF AMERICA WASHINGTON DC DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Russell, Steven J.

PDF Url : ADA324255

Report Date : 25 APR 1997

Pagination or Media Count : 195

Abstract : An extensive database of simultaneously obtained wall pressure and velocity measurements was acquired for a high Reynolds number, equilibrium turbulent flow. These data were obtained in both streamwise and spanwise measurement planes using an array of wall pressure transducers. Analyses of these data were performed to examine the spatial extent and convective features of turbulence producing structures. Several signal processing techniques were shown to extract detailed structural features of the turbulent motions. These techniques included digital band-pass filtering to discriminate between turbulent scales and a localized variance method for the detection of clusters of high frequency turbulent activity. Cross-spectral, cross-correlation, and conditional sampling methods applied to these data clearly show the dynamical relationships between coherent turbulent motions as well as their induced wall pressure signatures. Both pressure-velocity correlation results and conditionally averaged maps of the flow field sampled on peak wall pressure events, reveal a consistent correlation between large scale motions and near-wall, small scale turbulent production activity. The large scale vortical motions (or shear layers) extend across the turbulent boundary layer and exhibit Reynolds stress (turbulent production) characteristics. These findings are consistent with many of the proposed conceptual models of organized motions.

Descriptors :   *TURBULENT FLOW, *PRESSURE SIGNATURES, PRESSURE GRADIENTS, DATA BASES, ALGORITHMS, SIGNAL PROCESSING, PRESSURE TRANSDUCERS, TURBULENCE, TURBULENT BOUNDARY LAYER, VORTICES, COMPUTATIONAL FLUID DYNAMICS, FLOW VISUALIZATION, FLOW FIELDS, SHEAR STRESSES, PRESSURE DISTRIBUTION, BANDPASS FILTERS, REYNOLDS NUMBER, CROSS CORRELATION, MOMENTUM TRANSFER.

Subject Categories : Fluid Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE