Two different three-dimensional reconstruction techniques for the shape of gas bubbles flowing in a liquid are presented. The first technique is based on the Dynamic Generalized Hough Transform Algorithm, and the second on the Metaball Model. These techniques are suitable for analysis of turbulent two-phase bubbly flows. Both techniques require at least two views of the bubble intended for three-dimensional reconstruction, and can be used in either stereoscopic or orthogonal camera setups. Once the reconstruction is accomplished, the bubble images can be accurately removed from the images acquired during Particle Image Velocimtery or Shadow Image Velocimetry measurements. After removing the bubble images from PIV images, a typical analysis of the liquid phase can be performed. This improves the accuracy of the statistical analysis of the parameters of each phase.
Full-Volume, Three-Dimensional, Transient Measurements of Bubbly Flows Using Particle Tracking Velocimetry and Shadow Image Velocimetry Coupled with Pattern Recognition Techniques