Application of Molecular Tagging Towards Simultaneous Vibrational Temperature and Velocity Mapping in an Underexpanded Jet

Nitric oxide planar laser-induced fluorescence has been applied towards a transitional axisymmetric highly underexpanded jet flowfield to yield simultaneous maps of vibrational temperature and streamwise velocity. This novel laser diagnostic technique makes use of the photodissociation of seeded NO2 to produce spatially localized vibrationally excited and ground state NO which are then simultaneously probed. The experimental data have been compared against theoretical simulations to yield satisfactory results. Error analysis has shown that the technique can be used on a single-shot basis to produce instantaneous vibrational temperature and velocity mapping. Nomenclature 0 1N = initial population of the ground state 12B = stimulated absorption Einstein coefficient 21B = stimulated emission Einstein coefficient satI = saturation intensity LI = laser intensity 21A = spontaneous emission Einstein coefficient = fluorescence collection efficiency term fS = fluorescence signal intensity Bf = Boltzmann population fraction 12C = experimentally determined calibration constant 21vibE = energy difference between vibrational states 21rotE = energy difference between rotational states vibT = vibrational temperature rotT = rotational temperature k = Boltzmann constant "J = rotational quantum state x = spatial displacemen