• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 춘계학술대회논문집
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• pp.216-217
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• 2008

In recent years, scientific community has found renewed interest in hypersonic flight research. These hypersonic vehicles undergo severe aero-thermal environment during their flight regimes. During reentry and hypersonic flight of these vehicles through atmosphere real gas effects come into play. The analysis of such hypersonic flows is critical for proper aero-thermal design of these vehicles. The numerical simulation of hypersonic real gas flows is a very challenging task. The present work emphasizes numerical simulation of hypersonic flows with thermal non-equilibrium. Hyperbolic system of equations with stiff relaxation method are identified in recent literature as a novel method of predicting long time behaviour of systems such as gas at high temperature. In present work, Energy Relaxation Method (ERM) has been considered to simulate the real gas flows. Navier-Stokes equations A numerical scheme Advection Upstream Splitting Method (AUSM) has been selected. Navier-Stokes solver along with relaxation method has been used for the simulation of real flow over a circular cylinder. Pressure distribution and heat flux over the surface of cylinder has been compared with experiment results of Hannemann. Present heat flux results over the cylinder compared well with experiment. Thus, real gas effects in hypersonic flows can be modeled through energy relaxation method.

• 한국전산유체공학회지
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• 제20권1호
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• pp.99-104
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• 2015

Aero-optic phenomena cause the image position displacement on an imaging plane of the airborne optical/IR systems. Particularly, the aero-optic boresight error(BSE) is important factor for homing, positioning and aiming applications of hypersonic flight interceptor missile. In this paper, an estimating method of aero-optic BSE for a hypersonic flight vehicle is studied. A ray tracing method and a transform method of refractive index fields from flow density fields are combined with computational fluid dynamics(CFD) method.

• International Journal of Aerospace System Engineering
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• 제2권2호
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• pp.50-53
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• 2015

It would encounter some complicated flow fields, such as transition, separation, reattachment and disturbances, in the hypersonic flight. Thus, it is difficult to theoretically analyze the hypersonic aerothermodynamics effects, so that the ground-test simulation is thought of as one of the most important methods to improve the understanding level of the hypersonic aerothermodynamics. However, the aero-heating tests could not simulate all aerodynamics and geometry parameters in the real flight due to the differences between the experimental environments supplied by the ground facilities and the flight, so that the feasible technique for the ground-test simulation of the hypersonic aerothermodynamics effects is required to be advanced. The key parameters that are especially required to simulate for aero-heating tests are analyzed and one detailed approach is suggested to perform the experimental investigation on the hypersonic aero-heating effects in the ground facilities in this paper, and the tests are performed in the FD-20 gun tunnel of CAAA (China Academy of Aerospace Aerodynamics) to give out the data which could be used to confirm the equation from the theoretical analysis.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.27-30
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• 2007

In recent years, scientific community has found renewed interest in hypersonic flight research. These hypersonic vehicles undergo severe aero-thermal environments during their flight regimes. One of the most important topics of research in hypersonic aerodynamics is to find a reasonable way of calculating either the surface temperature or the heat flux to surface when its temperature is held fixed. This requires modeling of physical and chemical processes. Hyperbolic system of equations with stiff relaxation method are being identified in recent literature as a novel method of predicting long time behavior of systems such as gas at high temperatures. In present work, Energy Relaxation Method (ERM) has been considered to simulate the real gas flow over a 2-D cylinder. Present heat flux results over the cylinder compared well with the experiment. Thus, real gas effects in hypersonic flows can be modeled through energy relaxation method.

• 항공우주산업기술동향
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• 제7권1호
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• pp.43-55
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• 2009

20세기 전반 극초음속 공기흡입식 추진시스템에 대한 개념이 정립된 이래 항공우주기술선진국은 이러한 개념을 구현하기 위하여 꾸준히 연구를 진행하였으며 2004년 NASA의 X-43A Hyper-X가 마하 10의 극초 음속 공기흡입식 비행을 성공적으로 수행하였다. 현재 각 국에서는 이러한 극초음속 공기흡입식 추진시스템을 SSTO(Single Stage to Orbit) 또는 TSTO(Two Stage to Orbit) 개념의 재사용 위성 발사체 및 극초음속 미사일에 적용하기 위한 프로젝트가 본격적으로 진행되고 있다. 본 논문에는 미국, 유럽, 호주 아시아에서 개발하고 있는 극초음속 공기흡입식 추진시스템의 역사 및 현황과 이러한 추진시스템을 적용한 비행체, 미사일 개발 연구를 정리하였다.

• 한국항공우주학회지
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• 제43권3호
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• pp.243-256
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• 2015

극초음속 비행체 개발 연구의 일환으로 소형 발사체나 과학로켓을 이용한 여러 비행 시험 프로그램이 진행되었다. 국제 협력으로 진행된 호주의 HyShot 프로그램은 과학로켓을 이용한 대표적인 스크램제트 엔진 비행시험 프로그램이며, 이후 다양한 탑재체에 대한 유사한 극초음속 비행 시험 프로그램들이 진행되었다. 미국에서는 DARPA와 AFRL 및 ONR이 각각 Falcon HTV-2, X-51A 및 HyFly의 프로그램을 수행하였으며, 호주와 국제협력으로 HyCAUSE, HIFiRE 비행시험 프로그램을 수행하였다. 그 밖에도 프랑스는 X-51A과 유사한 LEA 프로그램을 진행하고 있으며, 러시아 및 중국, 인도는 극초음속 방위 체계 개발을 목표로 비행시험을 진행하고 있는 것으로 보인다. 본 논문에서는 향후 국내에서 유사 프로그램을 수행할 시 참고할 수 있도록, 이들 프로그램의 목표 및 기술 요소와 경과 및 프로그램 사이의 관계 등을 정리하였다.

• 한국항공우주학회지
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• 제48권9호
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• pp.731-743
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• 2020

극초음속 활공 비행체는 로켓 부스터에 의해 높은 고도로 올라가서 부스터에서 분리된 후 대기권 내에서 진행 방향을 바꾸면서 약 30~70km 고도에서 마하 5 이상의 극초음속으로 활공한다. 이는 포물선 궤적이 아닌 예측 불가능한 비행경로로 이동하므로 현재 미사일 방어 체계로 요격이 어렵다. 미국은 2010년대 초에 HTV-2와 AHW 비행시험을 수행하여 극초음속 활공 비행 가능성을 확인했고, 최근에 LRHW, ARRW 등 극초음속 활공 비행체 시스템을 개발하고 있다. 중국은 DF-ZF (WU-14) 활공 비행체를 2014년부터 비행시험을 수차례 수행했고 DF-17 미사일에 탑재하여 운용하고 있다. 러시아는 구소련 시절부터 극초음속 활공 비행체 연구를 수행했지만 실패를 거듭했고 근래에 Avangard (Yu-71) 활공 비행체를 SS-19 ICBM에 탑재하여 비행시험에 성공하였다. 본 논문에서는 미국, 중국, 러시아, 일본, 인도, 유럽에서 개발했거나 현재 개발 중인 극초음속 활공 비행체의 특성, 비행시험 사례 및 개발 동향을 고찰하였다.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.156.2-156
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• 2001

Hypersonic civil airplanes are recently heated up again in USA and Japan, but there are several difficulties when we obtain its optimal trajectories. In this paper, we formulated the trajectory optimization problem as an optimal control problem and solved it by the direct shooting method with the Genetic Algorithm, GA. The result shows it is effective to use this method for the trajectory optimization of the hypersonic flight.

• 한국전산유체공학회지
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• 제10권3호
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• pp.27-35
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• 2005

A design optimization of hypersonic flight vehicle has been studied by using upwind Navier-Stokes method and numerical optimization method. CFD method is linked to numerical optimization method by using a Bezier curve and a design optimization of blunt nose hypersonic flight vehicle has been studied. Heat transfer coefficient and drag coefficient are selected as objective functions or design constraints. The Bezier curve-based shape function was applied to blunt body shape.

• International Journal of Aeronautical and Space Sciences
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• 제14권3호
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• pp.215-221
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• 2013

The basic quantitative tool for the study of hypersonic rarefied flows is the direct simulation Monte Carlo method (DSMC). The DSMC method requires a large amount of computer memory and performance and is unreasonably expensive at the first stage of spacecraft design and trajectory analysis. A possible solution to this problem is approximate engineering methods. However, the Monte Carlo method remains the most reliable approach to compare to the engineering methods that provide good results for the global aerodynamic coefficients of various geometry designs. This paper presents the calculation results of aerodynamic characteristics for spacecraft vehicles in the free molecular, the transitional and the continuum regimes using the local engineering method. Results and methods would be useful to calculate aerodynamics for new-generation hypersonic vehicle designs.