Saver: A Peak Velocity Extraction Program for Advanced Photonic Doppler Velocimetry Analysis

Richtmyer-Meshkov instability (RMI) experiments offer a powerful, new tool for investigating materials strength at extreme strain rates, but obtaining peak velocities from the photon Doppler velocimetry (PDV) results of such tests is often subjective and time consuming. A new, semi-automated program, SAVER, was developed to address these concerns and was tested on data sets from previous RMI studies. Extreme surface velocities extracted using SAVER agreed well with human-determined values, and peak spike velocities – a key RMI metric – were reproduced to within ~ 8% in all cases. A re-analysis of materials strength based on these new SAVER values resulted in an estimated increase of ~ 20%, but no objective measure exists at this time to verify this result. While SAVER proved robust with regards to spectrogram quality, scatter in extracted velocities was seen to increase with decreasing signal quality – emphasizing the importance of PDV instrumentation and processing.