Semi-analytical Monte Carlo simulation of laser-induced fluorescence propagation in an optically participating spray

Chen, Ling-hong Roze, Claude Garo, Annie Girasole, Thierry Cen, Ke-fa Grehan, GerardA semi-analytical Monte Carlo (SMC) simulation was developed to simulate the propagation of laser-induced fluorescence (LIF) in an optically participating spray, which simultaneously exhibits spectrally dependent emission, anisotropic scattering, absorption, and re-emission. The SMC simulation is described and then applied to an experimental configuration of a cloud of polydisperse droplets composed of water and sulforhodamine B dye. In the SMC simulation, the collected LIF flux on the remote receptor element is calculated as the global contribution from the emissive source, single, twice, ... and nth collision events in any sequence. The effects on the fluorescence photons propagation of spray parameters like the dye concentration, droplets concentration, and droplets size are examined. Three spectral bands representing different optical properties are chosen to analyze the interference of absorption, scattering and re-emission on the detected LIF flux. The obtained spectral LIF flux distribution on the receptor demonstrates a "red shift" phenomenon