Decay of supersonic rectangular jet issuing from a nozzle with diagonal expansion ramps

Bogadi, Surendra; Sridhar, B. T. N.

doi:10.2298/tsci180614301b

Cited by 17 publications

(8 citation statements)

References 21 publications

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“…The location of axis switching for rectangular jet is found move upstream when two delta-tabs are used along the major axis of rectangular nozzle exit [18]. A diagonally placed ramp is also proved to be effective in controlling the mixing characteristics of Mach 1.8 rectangular jet from AR2 convergent-divergent nozzle [20]. In addition to modifying the mixing characteristics of jets, a jet control can also modify the jet acoustic characteristics.…”

Section: Introductionmentioning

confidence: 99%

Aspect Ratio Effect on Mach 1.5 Rectangular Jet Mixing

2021

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An experimental investigation on the mixing characteristics of Mach 1.5 rectangular jet emanating from aspect ratios (ARs) 2 and 3 convergent-divergent nozzles is carried out at nozzle pressure ratios (NPRs) 3, 3.69, 4 and 5, respectively. At overexpanded (NPR 3), correctly expanded (NPR 3.69) and underexpanded (NPRs 4, 5) levels of Mach 1.5 jet, the Pitot pressure measured along the centerline of AR2 and AR3 rectangular jets showed that the influence of aspect ratio on the jet mixing is not as strong as expected. The effect of aspect ratio is noticeable only in the core of both the jets. The core length of AR2 jet is shorter than AR3 jet at all the NPRs, which indicates faster mixing of AR2 jet with ambient fluid as compared to AR3 jet. But after core, the decay of AR2 and AR3 jets in the characteristic decay region remained almost same at all the NPRs except at correctly expanded NPR of 3.69, the AR3 jet decays slightly faster than AR2 jet. For all the cases, the jets have become fully developed together at far downstream location. The pressure profiles taken along major axis and minor axis of Mach 1.5 rectangular jets confirm the faster spreading of AR2 and AR3 jets along minor axis than along major axis. Both the jets are found to switch axes between 8D e to 10D e . The shadowgraph visualization reveals the complex structure of waves present in the major axis and minor axis planes of AR2 and AR3 rectangular jets.

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Section: Introductionmentioning

confidence: 99%

Aspect Ratio Effect on Mach 1.5 Rectangular Jet Mixing

2021

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“…For example, in passive jet control methods which employ grooves [1][2][3][4] or notches [5][6][7][8] on nozzle internal walls alter not only internal nozzle wall pressure distribution but also alter the shock structure of the emerging supersonic jet. The other type of passive control methods such as use of tabs [9][10][11], chevron configurations [12][13][14], lobes [15][16] and diagonal expansion ramps [17] for flight vehicle nozzles involve complex interaction features in the exiting supersonic flow that significantly determine the shock structure in the supersonic core, shear layer growth and its stability and also on the acoustic characteristics. The wall interaction by non-circular geometries of supersonic jets is of great importance in aerospace applications especially in the design of supersonic and hypersonic propulsion systems.…”

Section: Introductionmentioning

confidence: 99%

An experimental study on the interaction effects between a rectangular supersonic jet and a flat wall at different wall lengths

Manikanta,

Sridhar

2024

J Braz. Soc. Mech. Sci. Eng.

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An experimental investigation was undertaken to study the effect of placing a flat wall at the rectangular exit (Aspect Ratio =2) of a supersonic nozzle on the shock cell structure, and transverse deflection behavior of the jet issuing from the nozzle. The design exit Mach number (𝑀 𝑒 ) was 1.8. In the experiments, the length of the wall (𝐿 𝑤 ) and nozzle pressure ratio (NPR) were varied to explore their effect on the jet interaction with the wall.Schlieren images & wall pressure data obtained from the experiments were used to study shock cell structure and for calculation of two-dimensional normal force and moment coefficients. In over-expansion conditions, the interaction between the jet and the wall caused a downward deflection of the jet up to 𝐿 𝑤 = 𝐷 ℎ (hydraulic diameter). Underexpansion conditions of the jet made the jet deflect upward irrespective of the magnitude of 𝐿 𝑤 till 𝐿 𝑤 = 8𝐷 ℎ . The two-dimensional normal force and moment coefficients of the wall were more or less insensitive to the variation in 𝐿 𝑤 beyond 4𝐷 ℎ . However, for 𝐿 𝑤 < 4𝐷 ℎ , the jet expansion conditions determined the nature of variation with 𝐿 𝑤 .The effect of wall was such that reduction in wall-bound supersonic core length was maximum at 𝐿 𝑤 = 0.5𝐷 ℎ at over-expansion conditions and at 𝐿 𝑤 =𝐷 ℎ at under expansion conditions.

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“…Passive jet control methods used either geometrical modifications of the nozzle like use of cross wire, 1,2 notches, 3,4 tabs, [5][6][7] chevrons, [8][9][10] grooves, 11,12 expansion ramps, 13,14 or modifying the exit shape. [15][16][17][18][19] Active control methods employed some kind of actuator assisted device to interact with the jet to achieve jet control by changing the jet structure dynamically. Example of such methods included jet-evators and vanes.…”

Section: Introductionmentioning

confidence: 99%

Effect of flat wall length on decay and shock structure of a supersonic square wall jet

Tammabathula

Ghanta

Bandla

2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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Experiments were conducted to find the effect of wall length on the decay behaviour and shock structure of a supersonic wall jet issuing from c-d nozzle of the square-shaped exit. A straight flat wall of width same as the side length of the square was attached to the lip of the nozzle such that the leading edge of the wall and the side of the square aligned properly which allowed the supersonic jet to graze past the flat wall. Experiments were conducted with five different wall lengths, that is, [Formula: see text] = 0.5, 1, 2, 4 and 8. Wall pressure measurements were made from leading edge to the trailing edge of the wall along its centreline. Schlieren flow visualization of the jet flow over the wall for the different wall lengths revealed the shock pattern and the effect of the wall length on the shock structure. The shock structure and jet deflection were significantly affected due to the presence of the wall. There was an upward jet deflection for [Formula: see text] up to [Formula: see text] whereas a downward jet deflection was observed for [Formula: see text]. Noticeable changes in the shock structure were observed for the wall lengths up to 2 D h. The wall length also significantly affected the jet decay characteristics and supersonic core length. Maximum enhancement in jet decay and maximum reduction in supersonic core length resulted when the wall length was [Formula: see text]. However, when the wall length was increased to [Formula: see text], there was a significant reduction in jet decay and a recovery of [Formula: see text]. Presence of wall always resulted a reduction in Lsc irrespective of wall length. The wall effect was to induce a more precipitous pressure drop closer to the nozzle exit, and a more gradual drop farther from it for [Formula: see text] > [Formula: see text].

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Decay of supersonic rectangular jet issuing from a nozzle with diagonal expansion ramps

Cited by 17 publications

References 21 publications

Aspect Ratio Effect on Mach 1.5 Rectangular Jet Mixing

Aspect Ratio Effect on Mach 1.5 Rectangular Jet Mixing

An experimental study on the interaction effects between a rectangular supersonic jet and a flat wall at different wall lengths

Effect of flat wall length on decay and shock structure of a supersonic square wall jet

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