Wavefront sensors for optical diagnostics in fluid mechanics: application to heated flow turbulence and droplet evaporation

摘要

Abstract: Optical measurement techniques are extremely useful influid mechanics because of their non-invasive nature.However, it is often difficult to separate measurementeffects due to pressure, temperature and density inreal flows. Using a variation of a Shack-Hartmannwavefront sensor, we have made wavefront measurementsthat have extremely large dynamic range coupled withexcellent sensitivity at high temporal and spatialresolution. These wavefront variations can be directlyrelated to density perturbations in the fluid. We haveexamined several classes of flow includingvolumetrically heated gas, grid turbulence and dropletevaporation.!12