One-dimensional Interferometric Scattering Velocimetry for High-speed Flows

Interferometric Rayleigh scattering is an optical diagnostic technique that can be used to measure flow velocity in high-speed flows. Conventionally, the technique collects Rayleigh scattered light from a gas sample and passes it through a Fabry-Perot etalon to generate interference fringes on a camera. When the gas velocity increases, the Doppler shift in the scattered light introduces a shift in the spatial location of fringes and the flow velocity is estimated from this shift by a wavelength calibration of the camera pixels. Recently, the technique was extended to one-dimensional measurements by using a virtually imaged phased array instead of a Fabry-Perot etalon. The current work extends the application of such a one-dimensional interferometric system to seeded high-speed flows which makes the system work with much lower laser power, and discusses the details regarding the optimization of the system for high-speed flow applications.