Downstream fluidic injection based directionally targeted jet noise reduction system

Pankaj Rajput, Sunil Kumar

Research output: Chapter in Book/Report/Conference proceedingConference contribution


The main aim of this study is to analyze targeted jet noise reduction in a particular direction using controlled asymmetric downstream fluidic injection for a Mach 0.9 nozzle. Targeted reduction in the downward-emitted turbulent mixing noise can be achieved by strategically injecting high momentum fluid downstream of the jet exhaust. The effect of this localized asymmetric mixing enhancement on the far field noise is analyzed and it is observed that significant noise reduction can be obtained in a particular direction of interest. Two types of asymmetric injections-design based and operation asymmetries are outlined and investigated in this study. Detailed Large Eddy Simulations are performed on a hybrid block structured-unstructured mesh to generate the flow field which is then used for far-field noise computation. Aeroacoustic analogy-based formulation is used for computing the far-field noise. Mean flow measurements suggest that jet core lengths are shorter due to the enhanced mixing resulting from fluidic injection. The induced asymmetry due to the fluidic injection gives rise to an asymmetric acoustic field leading to targeted directional noise reduction (≈ 3.5S) in the far field. The advantage of this type of injection scheme is that it allows a certain degree of operational flexibility by allowing the user to choose a preferred direction of noise reduction and injecting fluid accordingly. This can help cut down the injection requirements and the associated thrust penalty with downstream injection, making the setup economically viable for practical implementation.

Original languageEnglish (US)
Title of host publication28th AIAA/CEAS Aeroacoustics Conference, 2022
PublisherAmerican Institute of Aeronautics and Astronautics Inc, AIAA
ISBN (Print)9781624106644
StatePublished - 2022
Event28th AIAA/CEAS Aeroacoustics Conference, 2022 - Southampton, United Kingdom
Duration: Jun 14 2022Jun 17 2022

Publication series

Name28th AIAA/CEAS Aeroacoustics Conference, 2022


Conference28th AIAA/CEAS Aeroacoustics Conference, 2022
Country/TerritoryUnited Kingdom

ASJC Scopus subject areas

  • Aerospace Engineering
  • Electrical and Electronic Engineering
  • Mechanical Engineering


Dive into the research topics of 'Downstream fluidic injection based directionally targeted jet noise reduction system'. Together they form a unique fingerprint.

Cite this