Gas dynamic and acoustic interactions with supersonic free shear layers

Experiments were conducted in a two-dimensional wind tunnel to study dynamics of large-scale structures in a planar compressible mixing layer. High-speed cinematic (300,000 frames/sec) Mie-scattering and shadowgraph techniques were employed to track the evolution of these structures in the mixing layer. A covariance algorithm was developed to obtain quantitative information about the size, shape, orientation and convection speed of these structures in the mixing layer from the digitally processed temporally resolved cinematographic images. The results for the pressure matched flows, show large ellipsoidal eddies in the mixing layer oriented at angles ranging from 25$\sp\circ-50\sp\circ$, which tilt away from and then towards the streamwise direction as they convect downstream. For the pressure mismatched cases, the eddies showed fluctuations in their angular orientation with time which scaled with the eddy passage frequency. The amplitude of these angular fluctuations was found to be a strong function of the non-dimensional streamwise pressure gradient parameter across the compression/expansion waves. The convection speed of the large-scale structures in pressure matched flows was found to be higher than that predicted by the isentropic relations, whereas for the pressure mismatched cases the convection speeds were found to be lower than the isentropic relation.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Aerospace Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Ramaswamy, Mahadevan Iyer

Contributors dc:contributor

• Loth, Eric

• Engineering, Aerospace

Statement dc:rights

• Copyright 1995 Ramaswamy, Mahadevan Iyer

Language dc:language

eng

Identifier

AAI9522162
(UMI)AAI9522162

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/22237