Turbulent fluctuations in the wakes of gasdynamic laser cusps

Abstract

Reacting mixtures of flowing gases are at the heart of many modern high-power laser devices. Shear layers and wakes that separate coflowing streams in such devices present possibilities of energy density and optical distortions in the laser beams. The difficult task of assessing these fluctuations can be greatly eased if they can be predicted, at least for the case where chemical reactions are absent. A description is given of the gas density fluctuations in the wakes of nozzle cusps as used in gasdynamic lasers for a wide range of exit Mach and Reynolds numbers, nozzle heat transfer, and gas properties such as specific heat ratio and Prandtl number.