Temperature and velocity determination of shock-heated flows with non-resonant heterodyne laser-induced thermal acoustics

摘要: Non-resonant laser-induced thermal acoustics (LITA), a four-wave mixing technique, was applied to post-shock flows within shock tube. Simultaneous single-shot determination of temperature, speed sound and flow velocity behind incident reflected waves at different pressure temperature levels are presented. Measurements were performed non-intrusively without any seeding. The paper describes the technique outlines its advantages compared more established laser-based methods with respect challenges tube experiments. experiments include argon nitrogen as test gas temperatures up 1000 K pressures 43 bar. experimental data calculated values based on inviscid one-dimensional wave theory. uncertainty is investigated for worst-case conditions resulting in relative standard deviations 1, 1.7 3.4 % Mach number, respectively. For all further conditions, stay well 95 % confidence intervals LITA measurement.