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Virginia Tech

Passive Scalar Measurements In Actively Excited Free Shear Flows

Abstract

dc:description.abstract

The objectives of this study were to implement a system to measure mixing in nonreacting flows and to study the mass transfer characteristics of two actively excited turbulent jets. This thesis describes the acquisition and analysis of phase-locked concentration field data using planar Mie scattering from smoke particles and planar laser-induced fluorescence of acetone. Both techniques were shown to be effective in providing information for the actively excited nozzles. However, the laser-induced fluorescence technique was superior for revealing detail in the flowfield structure. Spatial mode control techniques were applied to a triangular nozzle with vibrating actuators as the three sides and a swirl nozzle with pulsating tangential air jets. The effect of the different spatial modes on jet column development and the far fields of both nozzles is presented. Two- and three-dimensional iso-intensity contours, showing the relative intensity of light scattered by the nozzle fluid marker, were generated to show the flow structure. The areas inside the iso-intensity contours in the far field were also measured to determine relative effectiveness of nozzle fluid transport. Large scale structures were visible in the three-dimensional iso-intensity contours from both nozzles. In addition, the transport of seeded nozzle fluid was enhanced by the spatial mode excitation for both nozzles. Spatial mode excitation was also able to affect the shape of the far field contour. In particular, the first counterrotating helical mode, m=±1, generated the greatest effect on nozzle fluid transport and the most pronounced elliptical contour shape in the far field.

Degree

thesis:*
Name thesis:degree_name
Master of Science
Level thesis:degree_level
masters
Discipline thesis:degree_discipline
Mechanical Engineering
Department dc:contributor.department
Mechanical Engineering
Grantor dc:publisher
Virginia Tech
Year dc:date.issued
1998

Author and committee

dc:creator, dc:contributor.*
Author dc:creator
  • Marques, Steven Joseph Jr.
Chair dc:contributor.committeechair
  • Vandsburger, Uri
Committee members dc:contributor.committeemember
  • Dancey, Clinton L.
  • Roe, Larry A.

Subjects

dc:subject × 3

Rights

dc:rights
Statement dc:rights
  • In Copyright
Language dc:language.iso
en

Identifiers

dc:identifier.*
Dc Identifier Other
etd-5055101949711381
OAI identifier oai:identifier
oai:vtechworks.lib.vt.edu:10919/36759

Chain of custody

source
Harvested from
Virginia Tech
Base URL
vtechworks.lib.vt.edu/oai/request
Last updated
2026-07-22
Source record
OAI-PMH GetRecord
citation

Marques, Steven Joseph Jr.. Passive Scalar Measurements In Actively Excited Free Shear Flows. masters thesis, Virginia Tech, 1998. http://hdl.handle.net/10919/36759