Mach Wave Radiation by Mixing Layers. Part II: Analysis of the Source Field

1998 ◽  
Vol 12 (2) ◽  
pp. 91-108 ◽  
Author(s):  
N.D. Sandham ◽  
K.H. Luo ◽  
E.J. Avital
Keyword(s):  
Mixing Layers ◽  
Wave Radiation ◽  
Mach Wave ◽  
Source Field

Numerical Investigation of High Speed Free Shear Flow Instability and Mach Wave Radiation

2005 ◽  
Vol 4 (3) ◽  
pp. 325-343 ◽  
Author(s):  
Alexey N. Kudryavtsev ◽  
Dmitry V. Khotyanovsky
Keyword(s):  
High Speed ◽  
Large Scale ◽  
Shear Flows ◽  
Flow Instability ◽  
Mixing Layer ◽  
Mixing Layers ◽  
Linear Stability Theory ◽  
Wave Radiation ◽  
Mach Wave ◽  
Plane Jets

The linear stability theory is used to investigate the emergence, in supersonic free shear flows such as mixing layers and fully expanded plane jets, of supersonically travelling instability waves, which do not vanish in the ambient space. It is shown that, at supersonic convective Mach numbers, the slow and fast supersonic modes in the mixing layer as well as the sinuous supersonic mode in the plane jet should lead to Mach wave radiation. Direct numerical simulations are further used to study nonlinear stages of instability development in high-speed mixing layers and jets. They have shown that the formation of oblique shock waves attached to large-scale structures is observed in free shear flows forced by modes with supersonic phase speeds. The relevance of this phenomenon to the noise generation by high-speed jets is discussed.

Mach Wave Radiation by Mixing Layers. Part I: Analysis of the Sound Field

1998 ◽  
Vol 12 (2) ◽  
pp. 73-90 ◽  
Author(s):  
E.J. Avital ◽  
N.D. Sandham ◽  
K.H. Luo
Keyword(s):  
Sound Field ◽  
Mixing Layers ◽  
Wave Radiation ◽  
Mach Wave

scholarly journals Mach Wave Radiation from a Jet at Mach 1.92

2001 ◽  
Vol 13 (9) ◽  
pp. S3-S3 ◽  
Author(s):  
R. Darke ◽  
J. B. Freund
Keyword(s):  
Wave Radiation ◽  
Mach Wave

A study of Mach wave radiation using active control

2011 ◽  
Vol 681 ◽  
pp. 261-292 ◽  
Author(s):  
M. KEARNEY-FISCHER ◽  
J.-H. KIM ◽  
M. SAMIMY
Keyword(s):  
Large Scale ◽  
Near Field ◽  
Pressure Fluctuations ◽  
Hydrodynamic Pressure ◽  
Detailed Examination ◽  
Operating Conditions ◽  
Wave Radiation ◽  
Stagnation Temperature ◽  
Azimuthal Mode ◽  
Mach Wave

Mach wave radiation is one of the better understood sources of jet noise. However, the exact conditions of its onset are difficult to determine and the literature to date typically explores Mach wave radiation well above its onset conditions. In order to determine the conditions for the onset of Mach wave radiation and to explore its behaviour during onset and beyond, three ideally expanded jets with Mach numbers Mj = 0.9, 1.3 and 1.65 and stagnation temperature ratios ranging over To/T∞ = 1.0–2.5 (acoustic Mach number 0.83–2.10) were used. Data are collected using a far-field microphone array, schlieren imaging and streamwise two-component particle image velocimetry. Using arc filament plasma actuators to force the jet provides an unprecedented tool for detailed examination of Mach wave radiation. The response of the jet to various forcing parameters (combinations of one azimuthal mode m = 0, 1 and 3 and one Strouhal number StDF = 0.09–3.0) is explored. Phase-averaged schlieren images clearly show the onset and evolution of Mach wave radiation in response to both changes in the jet operating conditions and forcing parameters. It is observed that Mach wave radiation is initiated as a coalescing of the near-field hydrodynamic pressure fluctuations in the immediate vicinity of the large-scale structures. As the jet exit velocity increases, the hydrodynamic pressure fluctuations coalesce, first into a curved wavefront, then flatten into the conical wavefronts commonly associated with Mach wave radiation. The results show that the largest and most coherent structures (e.g. forcing with m = 0 and StDF ~ 0.3) produce the strongest Mach wave radiation. Conversely, Mach wave radiation is weakest when the structures are the least coherent (e.g. forcing with m = 3 and StDF > 1.5).

scholarly journals Conditional sampling analysis of high-speed schlieren movies of Mach wave radiation in a supersonic jet

2019 ◽  
Vol 145 (1) ◽  
pp. EL122-EL128 ◽  
Author(s):  
Masahito Akamine ◽  
Koji Okamoto ◽  
Susumu Teramoto ◽  
Seiji Tsutsumi
Keyword(s):  
High Speed ◽  
Supersonic Jet ◽  
Wave Radiation ◽  
Conditional Sampling ◽  
Mach Wave

Mach Wave Radiation: a Review and an Extension

2003 ◽  
Author(s):  
Anjaneyulu Krothapalli ◽  
Vijay Arakeri ◽  
Brent Greska
Keyword(s):  
Wave Radiation ◽  
Mach Wave
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