F sub 2 boundary layer measurement in a chemical laser slit nozzle flow

A sensitive F2 absorption diagnostic suitable for slit nozzle scanning was developed and applied to the measurement of an F2 boundary layer in an HF chemical laser flow. The F2 boundary layer profile was determined to be of exponential decay form with peak at the nozzle wall and of width approx. 1/3 the viscous boundary layer. The F2 concentration profile was displaced inwardly and slightly compressed by the H2 slit injection at the nozzle exit plane. The F2 profile apparently remains fairly intact in passing through the lasing zone.