Applications of underexpanded jets in hypersonic aerothermodynamics research

2012 ◽  
Author(s):  
Vladimir V. Riabov
Keyword(s):  
Underexpanded Jets

Mach number distribution over the axis of supersonic underexpanded jets

1968 ◽  
Vol 15 (6) ◽  
pp. 1153-1157 ◽  
Author(s):  
Yu. P. Finat'ev ◽  
L. A. Shcherbakov ◽  
N. M. Gorskaya
Keyword(s):  
Mach Number ◽  
Underexpanded Jets ◽  
Number Distribution ◽  
Mach Number Distribution

Effect of Mach number on the acoustic field of 2:1 elliptic-slot jet

2001 ◽  
Vol 105 (1043) ◽  
pp. 9-16 ◽  
Author(s):  
S. B. Verma ◽  
E. Rathakrishnan
Keyword(s):  
Mach Number ◽  
Fundamental Frequency ◽  
Acoustic Field ◽  
Major Axis ◽  
Shock Structure ◽  
Minor Axis ◽  
Noise Levels ◽  
Underexpanded Jets ◽  
Barrel Shock ◽  
Mach Numbers

Abstract The shock-structure and the related acoustic field of underexpanded jets undergoes significant changes as the Mach number Mj is increased. The present investigation is carried out to study the effect of Mach number on an underexpanded 2:1 elliptic-slot jet. Experimental data are presented for fully expanded Mach numbers ranging from 1.3 to 2.0. It is observed that the ‘cross-over’ point at the end of the first cell at low Mach numbers gets replaced by a normal shock at a highly underexpanded condition resulting in the formation of a ‘barrel’ shock along the minor-axis side with a ‘bulb’ shock formed along the major-axis side. The above change in shock structure is accompanied by a related change in the acoustic field. The amplitude of fundamental frequency along the minor-axis side grows with Mj but falls beyond Mj = 1.75. Along the major-axis side, however, the fundamental frequency does not exist at low Mach numbers. It appears at Mj = 1.75 but then falls at Mj = 2.0. The related azimuthal directivity of overall noise levels (OASPL) shows significant changes with Mj.

An experimental study of underexpanded sonic, coaxial, swirl jets

2004 ◽  
Vol 218 (1) ◽  
pp. 93-103 ◽  
Author(s):  
K-H Lee ◽  
T Setoguchi ◽  
S Matsuo ◽  
H-D Kim
Keyword(s):  
Static Pressure ◽  
Near Field ◽  
Flow Structures ◽  
Experimental Investigations ◽  
Pressure Measurements ◽  
Annular Nozzle ◽  
Free Jets ◽  
Underexpanded Jets ◽  
Secondary Stream ◽  
The Impact

The present study addresses experimental investigations of the near-field flow structures of an underexpanded sonic, dual, coaxial, swirl jet. The swirl stream is discharged from the secondary annular nozzle and the primary inner nozzle provides the underexpanded free jets. The interactions between the secondary swirl and primary underexpanded jets are quantified by a fine pitot impact and static pressure measurements and are visualized using a shadowgraph optical method. The pressure ratios of the secondary swirl and primary underexpanded jets are varied below 7.0. Experiments are conducted to investigate the effects of the secondary swirl stream on the primary underexpanded jets, compared with the secondary stream of no swirl. The results show that the presence of an annular swirl stream causes the Mach disc to move further downstream, with an increased diameter, and remarkably reduces the fluctuations of the impact pressures in the underexpanded sonic dual coaxial jet, compared with the case of the secondary annular stream with no swirl.

Visualization and analysis of the characteristics of transitional underexpanded jets

2013 ◽  
Vol 44 ◽  
pp. 140-154 ◽  
Author(s):  
Jingzhou Yu ◽  
Ville Vuorinen ◽  
Ossi Kaario ◽  
Teemu Sarjovaara ◽  
Martti Larmi
Keyword(s):  
Underexpanded Jets

Excess Noise from Supersonic Underexpanded Jets in Flight

1979 ◽  
pp. 264-274
Author(s):  
V. Sarohia ◽  
S. P. Parthasarathy ◽  
P. F. Massier ◽  
G. Banerian
Keyword(s):  
Excess Noise ◽  
Underexpanded Jets

Behavior of Underexpanded Jet Impinging on Sphere

2007 ◽  
Author(s):  
Masaki Endo ◽  
Yoko Sakakibara ◽  
Junjiro Iwamoto
Keyword(s):  
Flow Field ◽  
High Frequency ◽  
Laser Cutting ◽  
Separation Bubble ◽  
Jet Impingement ◽  
Screech Tone ◽  
Underexpanded Jet ◽  
Underexpanded Jets ◽  
Shock Region ◽  
Jet Structure

An underexpanded jet is utilized in industries as well as aviation field, e.g. to cool a body by the jet impingement, to remove molten metal in laser cutting, etc. One of the biggest problems is noise radiating from the jet which has high frequency, or screech tone. It is pointed out that the noise is closely related to the structure of the jet. In this paper, the underexpanded jets on a plate and hemispheres of different radii are visualized using the shadowgraph and Schlieren methods so as to analyze the jet structure, especially the flow field above the object, or the shock region. As a result, the radius of the hemisphere is found to have an effect not on the shape greatly, but on the location of the plate shock, and furthermore on the formation of separation bubble on the surface.

Thermal effect of strongly underexpanded jets on constructional elements of equipment of complicated form

1980 ◽  
Vol 15 (1) ◽  
pp. 92-97
Author(s):  
Yu. P. Balashov ◽  
Yu. I. Gerasimov ◽  
B. P. Plotnikov ◽  
A. G. Reshetin ◽  
P. N. Shklyaev
Keyword(s):  
Thermal Effect ◽  
Underexpanded Jets ◽  
Complicated Form
Sign in / Sign up

Export Citation Format

Share Document