Burst-mode velocimetry of hypersonic flow by nitric oxide ionization induced flow tagging and imaging
Boris S. Leonov, A. Moran, Simon W. North, Richard B. Miles
Abstract
This Letter describes, to the best of our knowledge, a new approach to flow tagging, nitric oxide (NO) Ionization Induced Flow Tagging and Imaging (NiiFTI), and presents the first experimental demonstration for single-shot velocimetry in a near Mach 6 hypersonic flow at 250 kHz. The mean velocity of 860 m/s was measured with a single-shot standard deviation of as low as 3.4 m/s and mean velocity uncertainty of 5.5 m/s. NiiFTI is characterized by a long fluorescence lifetime of nitrogen with 1 e decay of approximately 50 μ s measured in air. The method relies on a single nanosecond laser combined with a high-speed camera, creating an opportunity for the utilization of a typical nitric oxide (NO) laser-induced fluorescence (LIF) experimental setup with minor modifications as well as pulse-burst lasers (PBLs) for ultrahigh repetition rates.