Simple, Fast Nitric Oxide Planar Laser-Induced Fluorescence Model for Computational Fluid Dynamics Applications

Abstract

The current work demonstrates the efficacy of a simple and fast model for nitric oxide (NO) laser-induced fluorescence (LIF). The model is validated with experimental LIF spectra computed from captured images of fluorescence from a gas cell filled with a known amount of NO. These data are obtained for several segments of the NO fluorescence spectrum. The selected segments encompass LIF lines with rotational quantum numbers appropriate for low-to-moderate temperature flows. The spectra obtained using the current model are also compared to those obtained from other theoretical models, namely, LIFBASE and LINUS. The current model is based on a previously developed version of a two-level fluorescence model and is developed specifically for applications in computational fluid dynamics (CFD) where rapid on-the-fly evaluations are required due to the potentially large number of grid cells for which LIF is being computed. Good agreement between the experimental and theoretical results provides confidence in current LIF modeling for use with CFD. An example application of the current model in a Mach 6.5 hypersonic mixing flowfield is also presented.