Acoustic Control of Turbulent Jets

1. Subsonic Turbulent Jets.- 1.1. Aerodynamic Characteristics of Turbulent Jets. Coherent Structures.- 1.2. Coherent Structures and Hydrodynamic Instability.- 1.3. Acoustic Characteristics of Subsonic Turbulent Jets.- 1.4. Initial Conditions of Turbulent Jet Issue.- 1.4.1. Aerodynamic and Acoustical Parameters Characterizing the Issue Initial Conditions for Subsonic Submerged and Accompanying Turbulent Jets.- 1.4.2. Geometrical Parameters Determining the Issue Initial Conditions.- 1.5. Approaches to Turbulent Jet Control.- References.- 2. Control of Aerodynamic Characteristics of Subsonic Turbulent Jets.- 2.1. Susceptibility of Turbulent Jets to Weak Harmonic Acoustical Disturbances. Effect of Excitation Frequency.- 2.2. Effects of Acoustic Excitation Level.- 2.3. Effect on the Flow Regime in the Boundary Layer at the Nozzle Edge.- 2.4. Influence of Flow Initial Turbulence on the Efficiency of Jet Acoustical Excitation.- 2.5. Deformation of Jet Cross-Sections under Transversal Acoustical Excitation.- 2.6. Acoustical Excitation of a Jet Issuing from an Orifice with Sharp Edges.- 2.7. Vibration Excitation of a Turbulent Jet.- 2.8. Acoustic Excitation of High-Speed Jets.- 2.9. Changes in the Mode Composition on Turbulent Pulsations for a Jet under Acoustical Excitation. Localization of Pairing and Decay of Coherent Structures for a Jet under Acoustical Excitation. Mechanisms of the Jet Acoustical Excitation.- 2.10. Coflowing Stream Effect on Turbulent Mixing Intensification in Jets under Low-Frequency Acoustical Excitation.- 2.11. Tone Acoustical Excitation of Anisothermic Gas Jets.- 2.12. Effect of Two Opposite in Direction Sources of Transversal Acoustical Excitation of Identical Frequency in Phase and Antiphase.- 2.13. Effect of Acoustic Disturbances of Higher Azimutal Modes.- 2.14. Two-Frequency Acoustical Excitation of Jets. Subharmonic Resonance.- 2.15. Multi-Frequency Acoustical Excitation of Turbulent Jets.- 2.16. Acoustical Excitation of Noncircular Jets.- 2.17. Effect of the Nozzle Edge Sharp on Sensitivity of Jets to Acoustical Exitation.- References.- 3. Control of Acoustic Characteristics of Subsonic Turbulent Jets.- 3.1. Acoustic Characteristics of Near and Far Fields of Turbulent Jets under Acoustical Excitation.- 3.1.1. The Near Acoustical Field and Pressure Pulsations in a Jet.- 3.1.2. The Far Acoustical Field of a Jet.- 3.2. Acoustical Excitation on Anisothermic Jets.- 3.3. Acoustical Excitation of Jets in Coflowing Streams and Coaxial Jets.- 3.4. On Mechanisms of Noise Generation by Subsonic Turbulent Jets.- References.- 4. Effect of Intensive Acoustic Disturbances on Subsonic Jets.- 4.1. High-Amplitude Low-Frequency Periodical Excitation of a Circular Jet and Plane Mixing Layer.- 4.2. Flow Visualization in a Subsonic Circular Jet under Longitudinal and Transversal High-Amplitude Acoustical Excitation.- References.- 5. Self-Excitation of Turbulent Jet Flows..- 5.1. Self-excitation Schemes of Turbulent Jet Flows.- 5.2. Normal and Oblique Impingement of a Transonic Jet on a Baffle.- 5.2.1. Coherent Structures in Impact Jets.- 5.2.2. A Near-Wall Radial Jet.- 5.2.3. Suppression of Self-Excited Oscillations.- 5.3. Self-Excited Oscillations in Wind Tunnels with the Open Test Sections.- References.- 6. Numerical Simulation of Periodical Excitation of Subsonic Turbulent Jets.- 6.1. Direct Numerical Simulation of Turbulent Motion in the Initial Region of an Axisymmetric Jet under Low-Frequency Harmonic Excitation.- 6.2. Simulation of Plane and Circular Turbulent Jets under Low- and High-Frequency Harmonic Excitation Using the Method of Discrete Vortices.- 6.2.1. The Method of Discrete Vortices Simulates Plane and Circular Turbulent Jets for the Case of Ideal Incompressible Fluid.- 6.2.2. The metod of Discrete Vortices Simulates Round Turbulent Jets.- 6.3. Numerical Simulation of a Turbulent Mixing Layer on the Basis of the Nonstationary Reynolds Equations Closed by the Differential Model of Turbulence.- 6.4. Numerical Simulation of a Turbulent Jet Flows on the Basis of the Generalized Reynolds Equations (the Three- Term Extension). The Effects of Low- and High- Frequency Harmonic Excitation.- 6.5. An Interesting Analogy.- References.- 7. Supersonic Nonisobaric Turbulent Jets. Control of Aerodynamic and Acoustical Characteristics.- 7.1. Aerodynamic Characteristics of Supersonic Turbulent Jets.- 7.2. Mechanism of Noise Generation. Broadband Noise and Discrete Components.- 7.3. Acoustical Excitation of Supersonic Jets. Active Control.- 7.4. Control of Jet Parameters Using Jet Noise Screening. Passive Control.- References.- 8. Reduction of Turbojet Engine Noise.- 8.1. The Acoustical Silencer of Turbojet Noise.- 8.1.1. Model Tests of Cold Jets. Far Field.- 8.1.2. Model Tests of Hot Jets. Far Field.- 8.1.3. Full-Scale Tests of Turbojet Engines. Far and Near Fields.- 8.2. The Jet System for Reduciton of Supersonic Jet Noise. Suppression of the Discrete Component.- 8.3. Reduction of Turbojet Excess Noise Caused by Aeroacoustic Interaction.- References.- 9. Acoustical Approaches to Control of Self-Sustained Oscillations in Wind Tunnels with the Open Test Section.- 9.1. The Problem Statement and Measured Parameters.- 9.2. Suppression of Self-Oscillations under High-Frequency Acoustical Excitation of the Mixing Layer.- 9.2.1. Return Channel Loudspeacer Location.- 9.2.2. Injection/Suction Through a Narrow Slot Near the Nozzle Cut-off.- 9.3. Generation of Self-Oscillations and Creation of Homogeneous Pulsing Flow in the Wind Tunnel Test Section under Low- Frequency Excitation of the Mixing Layer.- 9.4. Suppression of Self-Sustained Oscillations Using Antinoise.- References.- 10. Interaction of a Mixing Layer with a Cavity.- 10.1. Separated Flow over a Cavity.- 10.2. Near-Wall Pressure Pulsations in a Cavity Flow and Approaches to Their Reduction.- 10.3. Pressure Pulsations in Transonic Wind Tunnels with the Closed Test Sections and Approaches to Their Reduction.- 10.4. Suppression of Self-Sustained Oscillations in Deadlock Branches of Gas Pipelines.- 10.5. Acoustical Control of Flows in Cavities.- References.