The coupled interactions between turbulent flow and thermal non-equilibrium (TNE) are physical and chemical processes with significant implications in turbulent heat transfer, fluid mixing, and fluid transport associated with high-speed vehicles and propulsion systems. Understanding the coupling mechanism allows one to utilize energy exchange for intelligent control of basic fluid dynamics processes. However, the elucidation of this mechanism necessitates quantifying the correlation of velocity fluctuations and scalar distributions. Thus, the development of reliable diagnostic techniques capable of simultaneous measurement of such quantities is necessary. Since turbulence is intrinsically three-dimensional, the measurement of the three-component velocity is imperative. The goal of this research is to develop a laser-based diagnostic technique as a non-intrusive approach to simultaneously measure three-component velocity and scalar fields to understand the coupling between turbulence and thermal non-equilibrium. It extends our recently developed Vibrationally Excited Nitric Oxide Monitoring (VENOM) method, which enables (1) the simultaneous measurement of 3D-velocity and planar temperature in cold, high-speed flows and (2) investigation of mean and instantaneous fluctuations in velocity and temperature. Experimental measurements of velocity and temperature across an oblique shock using the VENOM technique result in mean values within 21 m/s for the three components of velocity and 20 K for planar temperature when compared to oblique shock calculations. This extended stereoscopic VENOM system is expected to push forward the development of next-generation VENOM, i.e., dual-plane stereoscopic VENOM, for unprecedented characterization of fluid elements in three dimensions.
The coupled interactions between turbulent flow and thermal non-equilibrium (TNE) are physical and chemical processes with significant implications in turbulent heat transfer, fluid mixing, and fluid transport associated with high-speed vehicles and propulsion systems. Understanding the coupling mechanism allows one to utilize energy exchange for intelligent control of basic fluid dynamics processes. However, the elucidation of this mechanism necessitates quantifying the correlation of velocity fluctuations and scalar distributions. Thus, the development of reliable diagnostic techniques capable of simultaneous measurement of such quantities is necessary. Since turbulence is intrinsically three-dimensional, the measurement of the three-component velocity is imperative.
The goal of this research is to develop a laser-based diagnostic technique as a non-intrusive approach to simultaneously measure three-component velocity and scalar fields to understand the coupling between turbulence and thermal non-equilibrium. It extends our recently developed Vibrationally Excited Nitric Oxide Monitoring (VENOM) method, which enables (1) the simultaneous measurement of 3D-velocity and planar temperature in cold, high-speed flows and (2) investigation of mean and instantaneous fluctuations in velocity and temperature. Experimental measurements of velocity and temperature across an oblique shock using the VENOM technique result in mean values within 21 m/s for the three components of velocity and 20 K for planar temperature when compared to oblique shock calculations. This extended stereoscopic VENOM system is expected to push forward the development of next-generation VENOM, i.e., dual-plane stereoscopic VENOM, for unprecedented characterization of fluid elements in three dimensions.