Moderation of near-field pressure over a supersonic flight model using laser-pulse energy deposition

Furukawa, Daiki; Aoki, Y.; Iwakawa, Akira; Sasoh, Akihiro

doi:10.1063/1.4950783

Cited by 8 publications

(3 citation statements)

References 12 publications

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“…Some of these studies have reported that the energy deposition method is also effective to mitigate the sonic boom applying the shock-wave mitigation effect of energy deposition. [22][23][24] The drag reduction mechanisms enabled by energy deposition have been discussed using computational fluid dynamics. 12,15,25) Applying energy deposition a high-temperature low-density bubble, a so-called "thermal bubble" generated upstream, and the shock-wave is weakened when interacting with the bubble; the acoustic impedance of which is lower than that of the post-shock flow.…”

Section: Introductionmentioning

confidence: 99%

Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body

Iwakawa

Shoda

Majima

et al. 2017

Trans. Japan Soc. Aero. S Sci.

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Supersonic drag reduction performance using repetitive pulse energy depositions over blunt bodies was experimentally studied under two Mach numbers. The normalized drag reduction and energy deposition efficiency of Mach-1.92 over a 10-mm-dia. blunt-cylinder model were 8% and 1.2 at most, respectively. On the other hand, these values at Mach-3.20 over the same model were 22% and 6.2, respectively. The shock-wave deformation period using single-pulse energy deposition at Mach-3.20 was 64 ®s. This duration was shorter than that of 80 ®s at Mach-1.92, but the deformation magnitude on the model center axis of 40% at Mach-3.20 was larger than that of 15% at Mach-1.92. These experimental characteristics were consistent as solutions of the Riemann problem. Moreover, a drag reduction performance was much improved with a larger model diameter of 20 mm. Therefore, it has been experimentally demonstrated that the drag reduction performance due to energy deposition improves much at a high Mach number and with large model dimensions.

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Section: Introductionmentioning

confidence: 99%

Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body

Iwakawa

Shoda

Majima

et al. 2017

Trans. Japan Soc. Aero. S Sci.

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“…Laser energy deposition is an emerging technique to improve the aerodynamic performance of highspeed vehicles, and it has potential for various applications such as drag reduction [1,2], shock wave modification [3,4], and a controllable perturbation device for boundary layer transition studies [5].…”

Section: Introductionmentioning

confidence: 99%

Flow structure generated by laser-induced blast wave propagation through the boundary layer of a flat plate

Ukai

Kontis

Yang

2018

Aerospace Science and Technology

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Laser energy deposition generates localised flow structures that can be used as flow control devices in high-speed flows. In the present study, the interaction between a laser-induced blast wave and an incoming laminar boundary layer on a flat plate was experimentally investigated at a Mach 5 flow with three different unit Reynolds numbers. A hemispherical laser-induced blast wave (LIBW) is induced by focusing a 532 nm pulsed Nd:YAG laser beam on the surface of the plate. The hemispherical shaped fore wave front of the LIBW is locally transformed to an oblique shape, which results in a laser-induced oblique shock wave (LIOSW). As LIOSW propagates through the laminar boundary layer increases its thickness. With laser energy deposition near the leading edge of the flat plate, the LIOSW interacts and influences the leading edge shock wave (LSW). This interaction could contribute to the modulation of the LSW in scramjet intakes. A weak shock limb generated at the shape transition point of the LIBW or thermal spot due to laser-induced gas breakdown causes the boundary layer perturbation. The geometrical pattern produced due to the interaction between the LIOSW and the disturbed boundary layer remains similar to itself as it grows with time as well as at different local Reynolds numbers, 2.2 × 10 5 to 5.7 × 10 5 .

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“…Generally speaking, shock waves are of great interest in the fundamental research as well as applications, e.g. explosions and high-temperature physics [23], medical technology [24], rare metal recycling [25], aerospace engineering [26][27][28], electrohydrodynamics [29] and cold gas coating [30]. Beside the interest in fundamental researches, the current work may be of relevance for microfluidics [31] or even nanofluidics [32].…”

Section: Introductionmentioning

confidence: 99%

Laser-plasma induced shock waves in micro shock tubes

et al. 2017

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Shock wave generation with help of lasers or shock tubes, for example, is a common subject at macroscopic scale. On the other hand, the current tendency towards smaller scales becomes more and more important. In particular, shock waves in small channels or tubes with sub-mm or micron-sized diameter have attracted much interest within the last years. But downscaling of shock wave effects such as pressure decrease and Mach number attenuation during propagation, viscous and heat effects, laminar and turbulent flow is not necessarily straightforward from macro to micro or even nano range. Although several theoretical investigations are available in this new field, there is a strong demand on experiments, which are mostly missing due to the lack of suitable methods. The present work introduces a novel method for the generation of shock waves at microscale, namely laserinduced micro shock waves (LIMS). The LIMS method applies a femtosecond laser to induce an optical breakdown in a thin aluminum target located at the entrance of a micro tube. Subsequently, a shock wave is launched by the high pressure aluminum plasma and starts propagating into the tube. The topical work presents, for the first time, experimental investigations on direct micro shock wave generation and propagation at well-defined conditions in micron-sized tubes. They are performed for different conditions and tubes down to 50 μm diameter. Different from previous shock wave investigations in the mm-diameter range that involve pressure transducers, the present work applies non-contact measurements by optical methods. The experiments are supported by additional simulations. A one-dimensional numerical hydrocode is applied to simulate the shock wave generation process. Further propagation of the shock in a micro tube is analyzed by solving twodimensional Navier-Stokes equations. Both simulations agree well with the experimental results. Nomenclature L t laser pulse duration (fs-laser) E L laser pulse energy (fs-laser)

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Moderation of near-field pressure over a supersonic flight model using laser-pulse energy deposition

Abstract: Investigation on subsonic to supersonic flow around a sphere at low Reynolds number of between 50 and 300 by direct numerical simulation

Cited by 8 publications

References 12 publications

Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body

Mach Number Effect on Supersonic Drag Reduction using Repetitive Laser Energy Depositions over a Blunt Body

Flow structure generated by laser-induced blast wave propagation through the boundary layer of a flat plate

Laser-plasma induced shock waves in micro shock tubes

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