Directional noise reduction VIA asymmetric downstream fluidic injection

Pankaj Rajput, Sunil Kumar

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


The main aim of this investigation is to analyze directional noise reduction resulting from asymmetric high momentum fluidic injection downstream of a Mach 0.9 nozzle. Jet noise has been identified as one of the primary obstacles to increasing commercial aviation capacity. Microjets in cross flow are known to enhance turbulent mixing in the shear layer due to the induced stream-wise vortices. This enhanced mixing can be used for reorganizing the spatial distribution of acoustic energy. Targeted reduction in the downward-emitted turbulent mixing noise can be achieved by strategically injecting high momentum fluid downstream of the jet exhaust. Detailed Large Eddy Simulations were performed on a hybrid block structured-unstructured mesh to generate the flow field which was then used for near field and far field noise computation. Aeroacoustic analogy based formulation was used for computing far-field noise estimation. Benchmark cases were validated with preexisting experimental data sets. Mean flow measurements suggest shorter jet core lengths 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 in the far field as measured by pressure probes.

Original languageEnglish (US)
Title of host publicationAdvances in Aerospace Technology
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Electronic)9780791858349
StatePublished - Jan 1 2017
EventASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017 - Tampa, United States
Duration: Nov 3 2017Nov 9 2017


OtherASME 2017 International Mechanical Engineering Congress and Exposition, IMECE 2017
CountryUnited States


ASJC Scopus subject areas

  • Mechanical Engineering

Cite this

Rajput, P., & Kumar, S. (2017). Directional noise reduction VIA asymmetric downstream fluidic injection. In Advances in Aerospace Technology (Vol. 1). American Society of Mechanical Engineers (ASME).