An Investigation of the Irrotational Near Field of an Excited High Speed Jet.

The near-field pressure of a Mach 0.9 jet with Reynolds number of 6.2x10^5 has been investigated to examine the response of the jet to low-frequency forcing with localized arc filament plasma actuators (LAFPAs). The well-defined actuation phase allows for the phase averaging of the near-field pressure in order to separate the relevant features of the response from the background turbulence. The resulting phase-averaged signal illustrates a compact wave with a positive pressure excursion preceding a negative one. This is indicative of a large-scale structure (a vortex ring) that is generated by each impulsively seeded perturbation. The signature of these large-scale structures is shown to rapidly decay with radial distance from the jet. Simultaneous measurements of acoustic far field were also performed along with the near field, allowing the relationship between the two fields to be examined. Although the region near the jet shear-layer is largely hydrodynamic in nature, there is still significant correlation between the near-field pressure and the far-field acoustic around 30° polar angle, particularly as the jet evolves downstream past the potential core. This region is shown to shift upstream when the jet is forced.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor dc:publisher

The Ohio State University

Year dc:date

2013

Author dc:creator

• Alkandry, Hind

Contributors dc:contributor

• Samimy , Mo

• Aerospace Engineering
• Mechanical Engineering

Statement dc:rights

• unrestricted
• This thesis or dissertation is protected by copyright: all rights reserved. It may not be copied or redistributed beyond the terms of applicable copyright laws.

Language dc:language

English

Repository record dc:identifier

http://rave.ohiolink.edu/etdc/view?acc_num=osu1366213652

OAI identifier oai:identifier

oai:etd.ohiolink.edu:osu1366213652