Aerospace

21907 KiB

Open AccessArticle

Supersonic Flow Control Using Combined Energy Deposition

by O. A. Azarova

Aerospace 2015, 2(1), 118-134; https://doi.org/10.3390/aerospace2010118 - 18 Mar 2015

Cited by 25 | Viewed by 6965

Drag force control via energy deposition in an oncoming flow is a wide area of interest in aerospace sciences. Recently, investigations on the effect of combining energy sources have been conducted. The possibility of coupling microwave (MW) discharges or MW and laser energy deposition is discussed. In the present work, the flow details accompanying the interaction of a combined energy release and an aerodynamic body in a supersonic flow are considered numerically on the base of the Euler equations. Comparison with non-combined energy deposition is analyzed. The effect of introducing the internal part to the energy release on the drag force reduction is examined. The flows for blunt cylinder, hemisphere-cylinder and pointed body are considered for a wide class of the combined energy source characteristics. Freestream Mach number is varied from 1.89 to 3.45. Complicated unsteady vortex structures caused by the Richtmyer–Meshkov instabilities are shown to be the reason for the reduction in drag. The unsteady double vortex mechanism of the frontal drag force reduction and mechanism of the constantly acting vortices at the steady flow are described. Suppression of shear layer instability and large scaled flow pulsations as the result of the combined energy release effect is established. Complex conservative difference schemes are used in the simulations. Full article

(This article belongs to the Special Issue Recent Advances in SWBLI Research)

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12852 KiB

Open AccessArticle

The Development of Rocketry Capability in New Zealand—World Record Rocket and First of Its Kind Rocketry Course

by George Buchanan, David Wright, Christopher Hann, Hoani Bryson, Malcolm Snowdon, Avinash Rao, Adam Slee, Hans Philipp Sültrop, Bastian Jochle-Rings, Zane Barker, Abigail McKinstry, Claude Meffan, George Xian, Ryan Mitchell and XiaoQi Chen

Aerospace 2015, 2(1), 91-117; https://doi.org/10.3390/aerospace2010091 - 25 Feb 2015

Cited by 7 | Viewed by 15253

Abstract

The University of Canterbury has developed a rocket research group, UC Rocketry, which recently broke the world altitude record for an I-class motor (impulse of 320–640 Ns) and has run a rocketry course for the first time in New Zealand. This paper discusses the development and results of the world record rocket “Milly” and details all the fundamental elements of the rocketry final year engineering course, including the manufacturing processes, wind tunnel testing, avionics, control and the final rocket launch of “Smokey”. The rockets Milly and Smokey are an example of the design, implementation and testing methodologies that have significantly contributed to research and graduates for New Zealand’s space program. Full article

(This article belongs to the Special Issue Driving Forward Aerospace Innovation)

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2824 KiB

Open AccessReview

On Physical Aeroacoustics with Some Implications for Low-Noise Aircraft Design and Airport Operations

by Luís M. B. C. Campos

Aerospace 2015, 2(1), 17-90; https://doi.org/10.3390/aerospace2010017 - 4 Feb 2015

Cited by 6 | Viewed by 12041

Abstract

Air traffic is growing at a steady rate of 3% to 5% per year in most regions of the world, implying a doubling every 15–25 years. This requires major advances in aircraft noise reduction at airports, just not to increase the noise exposure due to the larger number of aircraft movements. In fact it can be expected, as a consequence of increased opposition to noise by near airport residents, that the overall noise exposure will have to be reduced, by bans, curfews, fines, and other means and limitations, unless significantly quieter aircraft operations are achieved. The ultimate solution is aircraft operations inaudible outside the airport perimeter, or noise levels below road traffic and other existing local noise sources. These substantial noise reductions cannot come at the expense of a degradation of cruise efficiency, that would affect not just economics and travel time, but would increase fuel consumption and emission of pollutants on a global scale. The paper reviews the: (i) current knowledge of the aircraft noise sources; (ii) the sound propagation in the atmosphere and ground effects that determine the noise annoyance of near-airport residents; (iii) the noise mitigation measures that can be applied to current and future aircraft; (iv) the prospects of evolutionary and novel aircraft designs towards quieter aircraft in the near term and eventually to operations inaudible outside the airport perimeter. The 20 figures and 1 diagram with their legends provide a visual summary of the review. Full article

(This article belongs to the Special Issue Driving Forward Aerospace Innovation)

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4200 KiB

Open AccessArticle

Shock Wave Diffraction Phenomena around Slotted Splitters

by Francesca Gnani, Kin Hing Lo, Hossein Zare-Behtash and Konstantinos Kontis

Aerospace 2015, 2(1), 1-16; https://doi.org/10.3390/aerospace2010001 - 5 Jan 2015

Cited by 4 | Viewed by 8414

Abstract

In the field of aerospace engineering, the study of the characteristics of vortical flows and their unsteady phenomena finds numerous engineering applications related to improvements in the design of tip devices, enhancement of combustor performance, and control of noise generation. A large amount of work has been carried out in the analysis of the shock wave diffraction around conventional geometries such as sharp and rounded corners, but the employment of splitters with lateral variation has hardly attracted the attention of researchers. The investigation of this phenomenon around two-dimensional wedges has allowed the understanding of the basic physical principles of the flow features. On the other hand, important aspects that appear in the third dimension due to the turbulent nature of the vortices are omitted. The lack of studies that use three-dimensional geometries has motivated the current work to experimentally investigate the evolution of the shock wave diffraction around two splitters with spike-shaped structures for Mach numbers of 1.31 and 1.59. Schlieren photography was used to obtain an insight into the sequential diffraction processes that take place in different planes. Interacting among them, these phenomena generate a complicated turbulent cloud with a vortical arrangement. Full article

(This article belongs to the Special Issue Recent Advances in SWBLI Research)

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Aerospace, Volume 2, Issue 1 (March 2015) – 4 articles , Pages 1-134

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