Flow visualization of the three‐dimensional, time‐evolving structure of a turbulent boundary layer

Experiments were performed using volumetric flow visualization to study the evolution of three‐dimensional boundary layer turbulence, and the interactions between inner and outer layer coherent structures. In the experiment, the inner and outer layers of a low Reynolds number (Rθ=705) turbulent boundary layer in air were seeded with smoke. A section of the boundary layer was rapidly scanned with a high intensity pulsed laser sheet, and the individual images were recorded using a high‐speed video camera. The video images were digitized and assembled into three‐dimensional volumes. A variety of image processing techniques and conditional sampling and statistical methods were then used to extract quantitative information from the three‐dimensional, time‐evolving visualization data.