Experimental Investigation of the Influence of Air-Tab Mach Number and Inclination Angle on Subsonic Jet Mixing

Jet mixing plays a vital role in aircraft design, particularly for jet engines. It contributes to improving combustion efficiency, reducing emissions, enhancing thrust production, and increasing engine durability, thereby boosting overall aircraft engine performance and reducing environmental impact. The air tab technique is a well-known and effective method for enhancing jet flow mixing without causing thrust loss. This study investigates the effects of air tab Mach number and inclination on mixing enhancement using pitot probe measurements. The primary jet, emerging from a convergent nozzle at a Mach number of 0.6, is controlled by air tabs set at Mach numbers of 0.5, 0.6, 0.7, and 0.8. The air tabs are positioned at the nozzle exit and tested at inclination angles of 900 and 450 . The study’s results show that air tabs are highly effective in enhancing mixing, with the distortion introduced by the air tabs increasing with higher Mach numbers. Specifically, using air tabs with a Mach number of 0.8 reduces the potential core length of the primary jet by 55%.