Control of Supersonic Jet using Air Tabs

The use of fluid injection in supersonic jet control techniques provides several benefits, including thrust augmentation and mixing enhancement. This study aimed to investigate the effect of air tabs on a Mach 2.1 supersonic jet by varying the injection pressure ratio (IPR) from 3 to 7 for fixed nozzle pressure ratios (NPR) of 4 and 7. The core length of the jet with and without air tabs was quantified by analyzing shadowgraph images under controlled conditions. The results showed that increasing the IPR from the air tabs at the nozzle exit (0D) led to a reduction in core length for the fixed NPRs of 4 and 7. The rate of core length reduction increased with increasing IPRs from 3 to 7. For NPR 4, the maximum and minimum core length reduction rates were found to be 32% and 8% for IPRs 7 and 3, respectively. Similarly, for NPR 7, the core length reduction rate was highest for IPR 7 (38%) and lowest for IPR 3 (8%). The results demonstrate that the use of air tabs induces stream-wise vortices, leading to mixing enhancement and a reduction in core length. © 2024. Carbon Magics Ltd.