Fiber Optic Approach to Time Resolved Tomographic Particle Image Velocimetry*

PIV has been heralded as an accurate means of extracting velocimetry information for the study of flow field phenomena. Many discoveries have been made utilizing the diagnostic, but the interpretation of the data is limited to two dimensions. In turbulent flows, three dimensionality is more often fact than exception. To accurately describe such flows, the PIV technique was expanded to 3D by use of tomography. The approach, though, suffers from lack of versatility, requires full optical accessibility, and is costly, limiting its use in laboratories. Presented are the results of a new approach to the tomographic PIV technique for acquiring time-resolved, three dimensional information to measure velocity and flame dynamics. The technology leverages fiber-optics and two high-speed cameras to capture eight image views of a domain to reconstruct and resolve a three-dimensional flow field. A camera sensor is split into four images by fiber couplings and the distal ends are arranged for 3D light-field capture.  The key is the compactness of the system. This unique technology combines the capability of a multi-camera array without the complexity of a multi-camera arrangement, and sacrifice of resolution.