Mach number dependence of the transition structure during jet diffusion in a supersonic jet

2021 ◽  
Vol 2021.58 (0) ◽  
pp. F012
Author(s):  
Takumi Miyagoshi ◽  
Watanabe Daisuke
Keyword(s):  
Mach Number ◽  
Supersonic Jet ◽  
Transition Structure

Experimental Investigation on Supersonic Jet Screech Tones

2012 ◽  
Vol 232 ◽  
pp. 213-217
Author(s):  
Jia Ming Li ◽  
Chun Bo Hu ◽  
Jun Hua Bai
Keyword(s):  
Mach Number ◽  
Field Distribution ◽  
Experimental Measurement ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Occurrence Frequency ◽  
Supersonic Jet Noise ◽  
Nozzle Size ◽  
Screech Tones ◽  
Peak Value

In order to investigate the characteristic of the supersonic jet screech tones, an experimental bench of the supersonic jet was designed and a free field noise signal acquisition system was established. Effects of the nozzle size and jet Mach number on jet noise sound field distribution was analyzed, through the result comparison of supersonic jet noise experimental measurement. Results indicate that the field distribution of supersonic jet screech tones is characterized with very strong directivity. Peak value of the screech tones decrease and occurrence frequency of the screech tones increase with the decreasing jet exit Mach number; occurrence frequency of the screech tones decrease with the increasing nozzle size, but the peak value change very less. The experimental measurement of supersonic jet noise provides mechanism research of sound production with data supports and references; and also provides the numerical modeling of supersonic jet noise with validation criteria.

Numerical Simulation of Supersonic Jet Control by Tabs with Slanted Perforation

2019 ◽  
Vol 0 (0) ◽  
Author(s):  
G. Ezhilmaran ◽  
Suresh Chandra Khandai ◽  
Yogesh Kumar Sinha ◽  
S. Thanigaiarasu
Keyword(s):  
Numerical Simulation ◽  
Mach Number ◽  
Near Field ◽  
Pressure Ratio ◽  
Supersonic Jet ◽  
Pressure Gradients ◽  
Nozzle Pressure Ratio ◽  
Nozzle Pressure ◽  
Jet Control ◽  
Different Diameters

Abstract This paper presents the numerical simulation of Mach 1.5 supersonic jet with perforated tabs. The jet with straight perforation tab was compared with jets having slanted perforated tabs of different diameters. The perforation angles were kept as 0° and 10° with respect to the axis of the nozzle. The blockage areas of the tabs were 4.9 %, 4.9 % and 2.4 % for straight perforation, 10° slanted perforation ( {{{\Phi }}_{\ }} = 1.3 mm) and 10° slanted perforation ( {{{\Phi }}_{\ }} = 1.65 mm) respectively. The 3-D numerical simulations were carried out using the software. The mixing enhancements caused by these tabs were studied in the presence of adverse and favourable pressure gradients, corresponding to nozzle pressure ratio (NPR) of 3, 3.7 and 5. For Mach number 1.5 jet, NPR 3 corresponds to 18.92 % adverse pressure gradients and NPR 5 corresponds to 35.13 % favourable pressure gradients. The centerline Mach number of the jet with slanted perforations is found to decay at a faster rate than uncontrolled nozzle and jet with straight perforation tab. Mach number plots were obtained at both near-field and far field downstream locations. There is 25 % and 65 % reduction in jet core length were observed for the 0° and 10° perforated tabs respectively in comparison to uncontrolled jet.

Experimental Investigation on Supersonic Jet Noise

2012 ◽  
Vol 588-589 ◽  
pp. 860-863
Author(s):  
Xiao Bo Peng ◽  
Jia Ming Li ◽  
Chun Bo Hu
Keyword(s):  
Mach Number ◽  
Sound Production ◽  
Supersonic Jet ◽  
Jet Noise ◽  
Occurrence Frequency ◽  
Correlated Noise ◽  
Experimental Conditions ◽  
Supersonic Jet Noise ◽  
Validation Criteria ◽  
Mixing Noise

A systematic study has been undertaken to quantify the effects of jet Mach number and nozzle size on the noise radiated by supersonic jets. All the tests were carried out at an experimental bench of the supersonic jet. Results indicate that the field distribution of supersonic jet screech tones is characterized with very strong directivity. Under the textual experimental conditions, if the jet Mach number remain unchanged, the diameter of nozzle throat increases gradually from 5mm to 8mm or 10mm, and the amplitude values of both the turbulent mixing noise and broadband shockwave correlated noise increase by 2-5dB, and the amplitude value change of the whistler type noise is not obvious, and the occurrence frequency of the whistler type noise decreases by more than 2000Hz; if the jet Mach number increases to 3.0 from 2.0, the amplitude value of the whistler type noise increases by more than 2dB, and the occurrence frequency of the whistler type noise decreases obviously. The experimental measurements of supersonic jet noise provide the sound production mechanism research on the supersonic jet noise with data supports and references and provide the numerical modeling of the supersonic jet noise with validation criteria.

Techniques for Supersonic Turbojet Noise Reduction

2012 ◽  
Author(s):  
David Munday ◽  
Dan Cuppoletti ◽  
Michael Perrino ◽  
Ephraim Gutmark ◽  
Markus O. Burak ◽  
...  
Keyword(s):  
Mach Number ◽  
Noise Reduction ◽  
Secondary Flow ◽  
High Performance ◽  
Supersonic Jet ◽  
Military Aircraft ◽  
Mach Numbers

Observations and simulations are presented of a supersonic jet from a nozzle representative of high-performance military aircraft such as the Saab Gripen. The nozzle has a design Mach number of 1.56 and is examined at its design condition with a surrounding secondary flow at Mach numbers of 0.0, 0.1 and 0.3. Chevrons and internal fluidic injection by microjets each reduce the noise generated by the main jet.

scholarly journals Numerical Study of Characteristics of Underexpanded Supersonic Jet

2020 ◽  
Author(s):  
Priyadharshini Murugesan ◽  
Arjun Biju Kumar ◽  
Akhil Teja Kambhampati ◽  
Shashank Pillai ◽  
Girish Chandar Chandrasekar ◽  
...  
Keyword(s):  
Mach Number ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Supersonic Jet ◽  
Working Fluid ◽  
Shock Cell ◽  
Specific Heats ◽  
Supersonic Core Length ◽  
The Mean ◽  
Jet Characteristics

Correlations for the supersonic jet characteristics, the mean shock cell length and the supersonic core length, have been obtained in terms of the jet parameters. The jet parameters considered in this study are the exit diameter of the nozzle (de), the design Mach number (Me), the nozzle pressure ratio (NPR) and the ratio of specific heats of the medium (γ). The parameters were varied as follows: exit diameters, from 0.5 to 25 mm; Mach number from 1 to 3; the NPR from 2.14 to 35. Initially, working fluid used is cold air and then effect of variation of γ is taken into consideration. The computational model has been validated and then used for all the numerical simulations. A quadratic fit for both characteristics has been obtained which is applicable to any supersonic jet. The correlations developed are valid within the respective ranges of the parameters stated above.

Supersonic Jet Control by Tabs with Slanted Perforation

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
G. Ezhilmaran ◽  
Suresh Chandra Khandai ◽  
S. Pavithrabalan ◽  
K. Udhayakumar
Keyword(s):  
Mach Number ◽  
Pressure Ratio ◽  
Supersonic Jet ◽  
Pressure Gradients ◽  
Nozzle Pressure Ratio ◽  
Pressure Decay ◽  
Core Length ◽  
Nozzle Pressure ◽  
Jet Control

Abstract Control of Mach 1.8 circular jet with slanted perforated tabs is studied experimentally. Two sets of perforated tabs were used for this study. The perforation angles were 0° and 30° with respect to axis of the nozzle. The blockage areas of the tabs were 5 %. The mixing enhancements caused by these tabs were studied in the presence of adverse and favorable pressure gradients, corresponding to nozzle pressure ratio (NPR) of 4, 5.74 and 8. For Mach number 1.8, jet NPR 4 corresponds to 30 % adverse pressure gradients and NPR 8 corresponds to 39.37 % favorable pressure gradients. The pressure decay characteristics and shadowgraph images of perforated tabs at different NPR were compared. There is 45 % and 65 % reduction in jet core length were observed for the 0° and 30° perforated tabs respectively in both pitot and shadowgraph experiments in comparison to uncontrolled jet.

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