Book contents
- Unsteady Combustor Physics
- Unsteady Combustor Physics
- Copyright page
- Summary Contents
- Detailed Contents
- Acknowledgments
- Introduction
- Overview of the Book
- 1 Basic Equations
- 2 Decomposition and Evolution of Disturbances
- 3 Hydrodynamic Flow Stability I: Linear Instability
- 4 Hydrodynamic Flow Stability II: Common Combustor Flow Fields
- 5 Acoustic Wave Propagation I: Basic Concepts
- 6 Acoustic Wave Propagation II: Heat Release, Complex Geometry, and Mean Flow Effects
- 7 Flame Sheet and Flow Interactions
- 8 Ignition
- 9 Internal Flame Processes
- 10 Flame Stabilization, Flashback, Flameholding, and Blowoff
- 11 Forced Response I: Flamelet Dynamics
- 12 Forced Response II: Heat Release Dynamics
- Index
- References
2 - Decomposition and Evolution of Disturbances
Published online by Cambridge University Press: 27 October 2021
- Unsteady Combustor Physics
- Unsteady Combustor Physics
- Copyright page
- Summary Contents
- Detailed Contents
- Acknowledgments
- Introduction
- Overview of the Book
- 1 Basic Equations
- 2 Decomposition and Evolution of Disturbances
- 3 Hydrodynamic Flow Stability I: Linear Instability
- 4 Hydrodynamic Flow Stability II: Common Combustor Flow Fields
- 5 Acoustic Wave Propagation I: Basic Concepts
- 6 Acoustic Wave Propagation II: Heat Release, Complex Geometry, and Mean Flow Effects
- 7 Flame Sheet and Flow Interactions
- 8 Ignition
- 9 Internal Flame Processes
- 10 Flame Stabilization, Flashback, Flameholding, and Blowoff
- 11 Forced Response I: Flamelet Dynamics
- 12 Forced Response II: Heat Release Dynamics
- Index
- References
Summary
A key focus of this text is to relate the manner in which fluctuations in flow or thermodynamic variables propagate and interact in combustion systems. In this chapter, we demonstrate that combustor disturbances can be decomposed into three canonical types of fluctuations – acoustic, entropy, and vorticity disturbances. This decomposition is highly illustrative in understanding the spatial/temporal dynamics of combustor disturbances [1]. For example, the velocity field can be decomposed into acoustic fluctuations, which propagate at the speed of sound with respect to the flow, and vorticity fluctuations, which are advected by the flow. This decomposition is important because, as shown in Chapters 11 and 12, two velocity disturbances of the same magnitude can lead to very different influences on the flame, depending on their phase speeds and space–time correlation. Section 2.9 further emphasizes how this decomposition provides insight into behavior measured in a harmonically oscillating flow field.
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- Information
- Unsteady Combustor Physics , pp. 27 - 80Publisher: Cambridge University PressPrint publication year: 2021