Automatic self-aligned focusing schlieren

Self-aligned focusing schlieren (SAFS) is a relatively new diagnostic that has proven particularly useful in the field of hypersonic aerodynamic experimentation. A modification of the SAFS technique is proposed to automatically sweep through multiple planes of focus in a fast, precise, and repeatable way, thereby acquiring quasi-three-dimensional data with a single data collection. The off-axis signal suppression of the configuration is quantified for features of different characteristic lengths, with the observation that larger features have longer depths of focus. Data are obtained for a steady supersonic jet and a hypersonic boundary layer as example cases for the automated setup.