Optical Flow Visualization

Abstract

Optical flow visualization techniques rely on the changes in flow density and hence the refractive index of the flow. Through various flow visualization techniques an image of the flow field is obtained which can be either qualitative, quantitative, or even both. The use of the appropriate visualization technique strongly depends on the flow field under investigation and the flow properties sought. The optical visualization techniques described here fall into the following categories: shadowgraphy, schlieren, moiré deflectometry, and interferometry. The optical tomography method which allows for the three‐dimensional reconstruction of the flow using two‐dimensional results is also briefly described.