Application of absorption filter planar Doppler velocimetry to sonic and supersonic jets

Abstract

An absorption filter planar Doppler velocimeter has been constructed and tested on a pressure-matched sonic jet and an overexpanded supersonic jet (A/design = 1-9). The current system can acquire single-velocity-component single-shot planar images (15-ns exposures) at 30 Hz. A unique aspect of the system is the use of a single camera and lens, made possible by the application of an image splitter system. This development reduces the expense and experimental complexity of the technique. The most extensive of the three data sets taken comprises 1100 centerline planes of instantaneous velocity acquired in the overexpanded supersonic jet. Mean and rms velocity fields are presented for this data set; a mean centerline and a mean transverse profile are extracted and compared with profiles from a computational fluid dynamics solution generated using the LARCK computer code employing a k-e turbulence model.