Time-resolved quantitative visualization of complex flow field emitted from an open ended shock tube using a wavefront measuring camera

Abstract

Quantitative visualization of shock-induced complex flow field emanating from the open end of a miniaturized hand-driven shock tube (Reddy tube) is presented. During operation, the planar shock wave of Mach number Mi=1.33 (±0.6%) is discharged through the low-pressure driven-section, kept open to ambient room condition. From the moment of shock discharge, its after effects of evolving flow field are recorded for 300 μsnear the exit of the tube by using a high resolution (16 MP) wavefront measuring camera (WC) setup. The ability of the camera to identify the amplitude and phase of the incident light wave is utilized to measure the flow induced change in phase of the interrogating light beam quantitatively. Information about the evolving flow field with a spatial resolution of 40 μm/pixel (for a field of view (FOV) 120 mm × 120 mm) and time resolution of 50 μsis recorded in repeated runs. The measured phase information is used in the iterative refraction tomographic scheme to recover the three-dimensional (3D) density distribution of the flow field quantitatively, which reveals the internal features of the domain. Computational fluid dynamic (CFD) simulation is carried out for the same experimental conditions and it is found that recovered experimental density distribution shows good agreement with the results obtained through CFD simulation.