@article {Balakrishnan:2016:0736-2935:959,
title = "Supersonic Impinging Jet Noise Reduction Using Co-axial Swirler",
journal = "INTER-NOISE and NOISE-CON Congress and Conference Proceedings",
parent_itemid = "infobike://ince/incecp",
publishercode ="ince",
year = "2016",
volume = "253",
number = "7",
publication date ="2016-08-21T00:00:00",
pages = "959-965",
itemtype = "ARTICLE",
issn = "0736-2935",
url = "https://ince.publisher.ingentaconnect.com/content/ince/incecp/2016/00000253/00000007/art00010",
author = "Balakrishnan, Paramasivam",
abstract = "Supersonic impinging jet noise reduction is an important problem, especially in STOL aircraft, VTOL aircraft and rockets. These types of impinging jets generate a larger amount of noise and highly unsteady flows, which lead to noisy environment, posing a hazard to humans and materials
in the proximity. The present study is carried out on supersonic impinging cold jets for nozzle pressure ratio (NPR) values of 2 and 5 with nozzle to plate distance (x / D) of 5, at different swirl numbers. The swirl flows are generated using co-axial curved blades and the results were compared
with non-swirl or free jets. The vane angles considered here are 20o, 40o, 60o and the swirl numbers ranged from 0 to 1.31. At NPR 2, the weak swirl number of 0.27 reduced the OASPL level by around 7 dB compared to non-swirl jets. The non-swirl jet emitted impinging tones at NPR 5 and the
swirl jet eliminated the impinging tones. At a high swirl number of 1.31, at NPR 5, OASPL is lowered by around 12 dB compared to non-swirl jets. The flow visualization study shows that the swirl disintegrates the repeated shocks and reduces the length of the shock cell system.",
}