Simultaneous velocimetry and thermometry of air by use of nonresonant heterodyned laser-induced thermal acoustics

Abstract

Nonresonant laser-induced thermal acoustics is used with heterodyne detection to measure temperature (285-295 K) and a single component of velocity (20-150 m/s) in an atmospheric pressure, subsonic, unseeded air jet. Good agreement is found with Pitot-tube measurements of velocity (0.2% at 150 m/s and 2% at 20 m/s) and the isentropic expansion model for temperature (0.3%).