AN EXPERIMENTAL STUDY OF THE TURBULENT MIXING OF A SUBSONIC AND A SUPERSONIC JET IN A CLOSED DUCT

摘要

An experimental study is presented of the turbulent mixing of two coaxial air jets at subsonic-supersonic speeds in a closed duct. The investigation was undertaken to obtain velocity profiles and axial velocity decay results and other turbulent flow properties with existing PIBAL equipment, and to analyze the conditions needed for an improved experiment.nBy using a suitable total pressure it was possible to correctly expand the ducted outer jet to ambient conditions. Negligible pressure gradients were found in a consider¬able region of the duct and all static and stagnation pressure measurements were made in the regime. The axial velocity decay was thus determined and compared with some results of Zakkay (reference 6) On the basis of the pressure measurements the flow field was divided into three mixing regions.