Experimental study on hysteresis phenomena of shock wave structure in an over-expanded axisymmetric jet

Matsuo, Shigeru; Setoguchi, Toshiaki; Nagao, Junji; Alam, Md. Mahbub; Kim, Heuy Dong

doi:10.1007/s12206-011-0730-3

Cited by 13 publications

(5 citation statements)

References 15 publications

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“…As expected, this length variation is strongly related to the structure of the shock wave reflection. In the over-expanded regime, the reflected shock wave does not produce an equal deflection, and the subsequent shock occurs in a closer position than in the under-expanded case [18]. For the two different flow regimes, fig.…”

Section: Flow Visualizationmentioning

confidence: 87%

On the Wall Pressure Fluctuations induced by a Supersonic Jet over the Wing pressure side

Meloni

Paola

Curcio³

et al. 2022

J. Phys.: Conf. Ser.

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Supersonic jet wing integrated configurations are expected to be relatively louder than subsonic installed configurations, increasing the wall pressure load transmitted inside the fuselage and stressing the wing/fuselage panels with very energetic and frequency localized supersonic effects. In this framework, a model-scale experimental investigation of an installed jet-wing configuration has been performed using a supersonic convergent-divergent nozzle interacting with a wing generated by a NACA4415 airfoil. The measurements have been carried out in the semi-anechoic chamber of the “G.Guj” Fluid Dynamic laboratory at the University Roma Tre. Wall pressure fluctuations are acquired at different axial locations in stream-wise and span-wise directions. Measurements are repeated for different wing radial positions and by varying the NPR between 2.2 and 2.6, thus exploring both over-expanded and under-expanded jet flow conditions. The flow features that characterize the different flow regimes were caught using the Background Oriented Schlieren (BOS) technique. Fluctuating pressure data, acquired with flush-mounted pressure transducers, were analysed in the frequency domain, considering a Fourier-based approach. A comparison of results obtained with an infinite flat plate has been used to highlight effects generated by the discontinuity related to the trailing edge.

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Section: Flow Visualizationmentioning

confidence: 87%

On the Wall Pressure Fluctuations induced by a Supersonic Jet over the Wing pressure side

Meloni

Paola

Curcio³

et al. 2022

J. Phys.: Conf. Ser.

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“…In the over-expanded regime the reflected shock wave does not produce an equal deflection, and the subsequent shock occurs in a closer position than in the under-expanded case (Hadjadj, Kudryavtsev & Ivanov 2004; Matsuo et al. 2011). Figure 5 shows the pixel displacement trends along the jet axis () normalised with respect to its mean value in the case of over-expansion (figure 5 a ) and under-expansion (figure 5 b ), respectively.…”

Section: Flow Qualificationmentioning

confidence: 99%

Experimental characterisation and data-driven modelling of unsteady wall pressure fields induced by a supersonic jet over a tangential flat plate

Meloni

Centracchio²,

Paola³

et al. 2023

J. Fluid Mech.

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This work deals with the investigation and modelling of wall pressure fluctuations induced by a supersonic jet over a tangential flat plate. The analysis is performed at several nozzle pressure ratios around the nozzle design Mach number, including slightly over-expanded and under-expanded conditions, and for different radial positions of the rigid plate. Pitot measurements and flow visualizations through the background oriented schlieren technique provided a general overview of the aerodynamic interactions between the jet flow and the plate at the different regimes and configurations. Wall pressure fluctuations were measured using a couple of piezoelectric pressure transducers flush mounted over the plate surface. The spectral analysis has been carried out to clarify the effect of the plate position on the single and multivariate wall pressure statistics, including the screech tone amplitude. The experimental dataset is used to assess and validate a surrogate model based on artificial neural networks. Sound pressure levels and coherence functions are modelled by means of a single fully connected network, built on the basis of a recently implemented fully deterministic topology optimization algorithm. The metamodel uncertainty is also quantified using the spatial correlation function. It is shown that the flow behaviour as well as the screech and broadband noise signatures are significantly influenced by the presence of the plate, and the effects on spectral quantities are correctly reproduced by the proposed data-driven model that provides predictions in agreement with the available data.

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“…Menon & Skews (2010) analysed the evolution of rectangular jets and other non-axisymmetric jets for various pressure ratios corresponding to the underexpanded regime and observed that the shock transition process depends on the aspect ratio and shape of the nozzle exit. Experimental and computational studies of the shock interactions in the overexpanded axisymmetric jets have been carried out by Matsuo et al (2011). They experimentally verified the presence of shock transition in the overexpanded jets for different nozzles exit Mach numbers.…”

Section: Introductionmentioning

confidence: 98%

“…Experimental and computational studies of the shock interactions in the overexpanded axisymmetric jets have been carried out by Matsuo et al. (2011). They experimentally verified the presence of shock transition in the overexpanded jets for different nozzles exit Mach numbers.…”

Section: Introductionmentioning

confidence: 99%

Prediction of Mach stem height in compressible open jets. Part 1. Overexpanded jets

2022

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The flow from a supersonic nozzle when operated at off-design conditions exhibits a wide variety of complex flow structures. The prominent ones are the shock reflections inside the jet. The two main types of shock interactions are the regular reflection (RR) and Mach reflection (MR). The prominent characteristic change in the shock pattern when an RR transforms into an MR is the appearance of the Mach stem with a subsonic region downstream of it. The estimation of the Mach stem height gives the size of the subsonic domain and is a direct method to predict the transition from RR to MR or vice versa. The present study is carried out to estimate the size of the Mach stem in an inviscid jet in the overexpanded regime. The analytical methods employed here are the extension of the techniques developed to estimate the Mach stem size in the wedge flows by Li & Ben-Dor (J. Fluid Mech., vol. 341, 1997a, pp. 101–125), Mouton & Hornung (AIAA J., vol. 45, issue 8, 2007, pp. 1977–1987) and Bai & Wu (J. Fluid Mech., vol. 818, 2017, pp. 116–140). The results from the analytical formulation have been compared with the high resolution computational and experimental results. The analytical method reveals that the open jet has a unique, stable MR configuration and forms an upper limit for achievable Mach stem height for the wedge flows. Apart from the estimation of Mach stem height, the growth rates of Mach stem where the RR–MR transition takes place are also calculated and compared with the ones corresponding to wedge flows.

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Experimental study on hysteresis phenomena of shock wave structure in an over-expanded axisymmetric jet

Cited by 13 publications

References 15 publications

On the Wall Pressure Fluctuations induced by a Supersonic Jet over the Wing pressure side

On the Wall Pressure Fluctuations induced by a Supersonic Jet over the Wing pressure side

Experimental characterisation and data-driven modelling of unsteady wall pressure fields induced by a supersonic jet over a tangential flat plate

Prediction of Mach stem height in compressible open jets. Part 1. Overexpanded jets

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