• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.511-514
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• 2009

In this study, the combustion characteristics of hybrid rocket fuel with tapered grain port were studied. The regression rate was increased about 17.5% by using the convergence port shape fuel. On the other hand, in case of divergence port shape fuel, any notable difference of regression rate was not observed when compared with regression rate of the cylindrical port shape fuel. Also, in case of convergence port shape fuel, characteristic velocity efficiency was increased. From these results, one can notice that convergence port shape of hybrid rocket fuel can be effective configuration in terms of improvement of combustion efficiency and performance.

• Composites Research
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• v.13 no.2
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• pp.61-71
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• 2000

Today, the use of composite materials become an essential part in the design and manufacturing process of the flight vehicles to reduce the structural weight. Since the structural properties can be varied largely due to the stacking sequence of ply angles, it is very important problem to determine the optimized ply angles under a design objective. Thus, in this study, the analysis of static aeroelastic optimization of a composite wing has been performed. An analytical system to calculate and optimize tile aero-structural equilibrium position has been developed and incorporated with the genetic algorithm. The effects of stacking sequence on the structural deformation and aerodynamic distribution have been studied and calculated with the condition of minimum structural deformation for a swept-back composite wing. For the set of practical stacking angles, the design results to maximize the performance of static aeroelasticity are also presented.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.8-14
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• 2011

In this paper, the combustion characteristics of hybrid rocket fuel with tapered grain port were investigated experimentally. The charging efficiency of convergent and divergent port shape fuel with $1^{\circ}$ taper angle was 6.8% higher than that of cylindrical port shape fuel. The regression rate was increased about 17.5% by using the convergent port shape fuel. On the other hand, in case of divergent port shape fuel, no notable difference of regression rate was observed when compared to that of the cylindrical port shape fuel. In the case of convergent port shape fuel, characteristic velocity and its efficiency were notably increased with respect to cylindrical port fuel. It was found that convergent port shape of hybrid rocket fuel can lead to a better option compared to the conventional cylindrical port in terms of combustion efficiency and performance improvement.

• Proceedings of the KSME Conference
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• 2005.11a
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• pp.57.1-57.1
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• 2005

• The monthly packaging world
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• s.9
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• pp.70-77
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• 1994

일본포장관리사회는 93년도 일본 포장업계 10대 뉴스에서 자국 포장업계가 93년도 한 해 '미증유의 시련기' 였음을 제일 첫째로 꼽고 있다. 거품경제 붕괴 뒤의 경기 후퇴, 엔고 등 나름대로 이유가 있었겠지만 국내 포장업계 사정도 일본의 경우와 크게 다르지 않았을 것으로 사려된다. 구랍 16일 한국포장협회 회의실에서 각 부문의 관계자들이 참석한 가운데 열린 좌담회를 통해 93년도 국내 포장산업의 회고와 94년도 전망을 들어본다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1228-1233
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• 2000

A new planform of a wing having two sweep angles is proposed to enhance the aeroelastic stability of a swept-forward wing. The double-swept wing has two sweep angles with inboard wing swept-back and outboard wing swept-forward. Aeroelastic analysis is performed with the finite element method to model wing structure and the doublet point method to predict aerodynamic loads. The sweep angle of the inboard wing is varied in this analysis while the outboard wing is swept forward to a pre-selected amount. The results show that the aeroelastic stability can be drastically enhanced by adjusting the sweep angle of the inboard wing. The effect of the fiber orientation in the double-swept composite wing is studied and the proper ply angle is identified to maximize critical speed.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.39 no.8
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• pp.725-734
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• 2011

At high angles of attack, aircraft dynamics can display an oscillatory lateral behavior that manifests itself as a limit cycle known as wing rock. In this paper, a classical and neural network based adaptive control design methods of adaptively stabilizing the oscillatory motion by adapting uncertainties are described in detail. All methods are simulated and compared using a model for an 80o swept delta wing.

• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.4
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• pp.39-45
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• 2003

Of the various means for active trajectory correction, a thrust vector control system represents the only principle independent of missile external forces so that this method is operative. The purpose of this study is to analyze the characteristic of jet vane TVC(Thrust vector control) system among mechanical jet deflection. To ensure high performance leading edge shape, aspect ratio and ablated condition is optimized. Supersonic flow system, jet vanes and nozzle with Mach number 2.88 and under expansion ratio 2 were designed to study aerodynamic characteristics of leading edge shape, aspect ratio and ablated conditions.

• Aerospace Engineering and Technology
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• v.1 no.2
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• pp.1-10
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• 2002

Flow computations around forward sweep wing small aircraft have been conducted in this study. The main-wing of the forward-wing small aircraft is composed of two planforms: the inboard wing section with backward sweep angle which is known as strake and the outboard wing section with forward sweep angle. The geometrical discontinuity or kink generated by the combination of these two different planforms requires detailed flow analysis around wing. Four different solvers were used to calculate aerodynamic data and the accuracy of each method is examined. For the convenience of grid generation over the aircraft geometry, the overset grid method was applied. Through this calculation, the basic aerodynamic data of the forward-wing aircraft were provided and the aerodynamic characteristics of the wing is expounded.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.42 no.1
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• pp.1-9
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• 2014

The present study was conducted by using fast-responding PSP technique to measure the surface pressure on a small-scale rotor blade in hover. Also, the study was performed to verify the accuracy and investigate its possibility of PSP application for rotor blade pressure measurement. Pulsed laser which has 532 nm wavelength was used as a light source. Lifetime measurement technique was applied. Also, the coated paint on a rotor blade was porous PSP which has faster response time than conventional PSP. The blades had NACA0012 airfoils. The length of rotor blade was 340 mm and chord was 40 mm with rectangular shape 1 set, and 4 sets had several tip sweepback angles. The measured results qualitatively showed that the upper surface pressure decreases with increasing the collective pitch angle. Quantitative pressure coefficients of PSP results were higher approximately 0.4 to 0.7 than the pressure tap data of the NASA experiment.