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 (R_θ=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.