Measurements of Periodic Reynolds Stress Oscillations in a Forced Turbulent Premixed Swirling Flame
Abstract
This work is motivated by the thermoacoustic instability challenges associated with ultra-low emissions gas turbine (GT) combustors. It demonstrates the first use of high-speed dual-plane orthogonally-polarized stereoscopic-particle image velocimetry (PIV) and synchronized OH planar laser-induced fluorescence in a premixed swirling flame. We use this technique to explore the effects of combustion and longitudinal acoustic forcing on the time- and phase-averaged flow field—particularly focusing on the behavior of the Reynolds stress in the presence of harmonic forcing. We observe significant differences between ensemble-averaged and time-averaged Reynolds stress. This implies that the large-scale motions are nonergodic, due to coherent oscillations in Reynolds stress associated with the convection of periodic vortical structures. This result has important implications on hydrodynamic stability models and reduced-order computational fluid dynamics simulations, which do show the importance of turbulent transport on the problem, but do not capture these coherent oscillations in their models.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Aug 31, 2018
- Source ID
- 10.1115/1.4040686
Entities
People
- Benjamin Emerson
- Christopher A. Fugger
- Christopher M. Douglas
- James Gord
- Jamie Lim
- Josef Felver
- Naibo Jiang
- Sukesh Roy
- Tim Lieuwen
- Tongxun Yi
- Travis Smith
Organizations
- Air Force Research Laboratory
- Georgia Tech