NASA Goddard Institute for Space Studies, Columbia University, New York, New York, 10025, U.S.A.
Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey, 08544, U.S.A.
(Received 10 March 1997, Publication Date 23 May 1997)
A low Reynolds number, zero pressure gradient, incompressible turbulent boundary layer was investigated using a volumetric imaging technique. The Reynolds number based on momentum thickness was 701; the flow was tagged with a passive scalar from two spanwise dye slots to distinguish between fluid motions originating in the inner and outer portions of the boundary layer. The resulting volumetric scalar field was interrogated using a laser sheet scanner developed for this study. Two- and three-dimensional time-dependent visualizations of a fifty volume time series are presented. In the outer portion of the boundary layer, scalar structures were observed to lie along lines in the x-z plane, inclined to the x-direction in the range ±50 . The ejection of brightly-dyed fluid packets from the near-wall region was observed to be spatially organized, and related to the passage of the large-scale scalar structures.
Next Section: Introduction
2. Acquisition and Visualization of the Volumetric Data Set
3. Results: Two- and Three-Dimensional Visualizations