• Journal of the Korea Institute of Military Science and Technology
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• v.20 no.4
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• pp.467-473
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• 2017

In this paper, impact characteristics of a water entry gliding vehicle were analyzed using a finite element method. To guarantee the validity of analysis results, a convergence test was performed for several ratios of Euler and Largrange mesh sizes. The impact coefficient was calculated with respect to entry angles and angle of attacks. It can be observed that the impact coefficient was large at a high cross-section gradient and was also affected by cavitation. This study could be useful in the preliminary design stage of a water entry bomb development.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.6
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• pp.547-556
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• 2010

For the safety of aircraft and accuracy of bombs, many companies have researched the new concept of adaptive kit to flying-bombs. For the long distance flying, it's normally used deployed high-aspect ratio wing because of limited volume. The probabilities of large elastic deformation and flutter are increased due to decreased stiffness of high-aspect ratio wing. In this paper, computational fluid dynamics and computational structure dynamics interaction methodology are applied for prediction of aerodynamic characteristics. FLUENT and ABAQUS are used to calculate fluid and structural dynamics. Code-bridge was made base on the compactly supported radial basis function to execute interpolation and mapping. There are some differences between rigid body and fluid-structure interaction analysis which are results of aerodynamics characteristics due to structural deformation. Small successive vibration was observed by interaction.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.2
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• pp.183-190
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• 1994

본 연구에서는 항공기 사고의 대부분을 차지하는 이${\cdot}$착륙단계중에서, 이륙직 후 저고도에서 동력이 상실되었을 경우에 이륙활주로 방향으로 Turning Back하는 것은, 어떠한 안전 한계를 지니고 있는지를 선회 소요시간과 고도손실, 선회율과 활공속도와의 관계 등의 이론적인 근거에 기초하여 분석하고자 한다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.41 no.4
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• pp.314-318
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• 2013

Tests and evaluations following the U.S. MIL-HDBK/STANDARD were successfully conducted to assure the performance of the air-to-surface guidance kit which was developed first in Korea. Various ground tests confirmed the operation capability and reliability of the guidance kit, and flight tests proved very good mid-range gliding performance and accuracy of the gliding bomb which was a general purpose bomb with the guidance kit.

• Journal of the Korean housing association
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• v.1 no.1
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• pp.103-111
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• 1990

This study has researched on the utilization of living space through interview with a owner of the MAN-CHUI-DANC. The aim of the study is to grasp-the resident living and dwelling ceremony through rites of passase of the MAN-CHUI-DANG among the upper class residence of Korean traditional house A result of this study , Korean traditional house have been so inhered multipurpositive and adaptability that dwelling living space for the rites of passage is always separation, transition, coordination as living aspect.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2001.05a
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• pp.560-563
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• 2001

본 논문에서는 대차의 인적ㆍ물적ㆍ지적 자원을 효과적으로 활공할 수 있도록 효율적인 연결 모델을 제시하여 지러 중소기업의 기술개발과 생산성 향상을 도모하기 위산 산학연정보망 시스템을 구축하였다. 그리고 시스템에 의해 제공될 수 있는 주요 서비스로는 전문기술과 인력정보 제공, 전문인력에 대한 프로필 제공, 중소기업의 연구 개발 인프라를 지원하기 위한 시험연구 설비 및 기자재에 대한 정보제공, 기타 중소기업에 서 필요로 하는 정보를 제공할 수 있는 시스템을 설계 및 기술하였다.

• Proceedings of the KIPE Conference
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• 2015.07a
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• pp.133-134
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• 2015

본 논문에서는 유도형 활공 탄약의 방향과 자세 제어를 위한 4축 조종 날개의 위치 제어용 Sensorless BLDC 전동기 구동 시스템을 개발하였다. HILS(Hardware in the loop system)를 이용하여 유도형 탄약의 발사 조건과 비행 환경을 시뮬레이션하면서 비행 시 발생하는 공력 부하를 기구부로 재현하였고 이러한 조건하에서 4축 조종 날개의 위치 제어 특성을 확인함으로써 개발된 구동 시스템의 성능을 검증하였다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.519-526
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• 2009

This paper describes a research result of a external shape optimization study to maximize the range of the guided missile with canards and tailfins in atmospheric flight. For this purpose, the external shape optimization program which can enhance the range of a missile was developed, incorporated with the trajectory analysis and the optimization technique. In the trajectory analysis part, Missile DATCOM which utilizes the semi-empirical method was directly connected to the trajectory code to supply the aerodynamic coefficients efficiently at every time step. In the gliding flight trajectory after apogee, a maximum $C_L/C_D$ trim condition calculation module was attached under the assumption of the missile continuously flying at maximum $C_L/C_D$ condition. In the optimization part, a Response Surface Method(RSM) was adopted to reduce the computing time.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.49 no.1
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• pp.21-30
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• 2021

Mid-course trajectory of the missiles equipped with seeker should be designed to detect target within FOV of seeker and to maximize the maneuverability at the point of transition to terminal guidance phase. Because the trajectory optimization problems are generally hard to obtain the analytic solutions due to its own nonlinearity with several constraints, the various numerical methods have been presented so far. In this paper, mid-course trajectory optimization problem for boost-glide missiles is calculated by using SOCP (Second-Order Cone Programming) which is one of convex optimization methods. At first, control variable augmentation scheme with a control constraint is suggested to reduce state variables of missile dynamics. And it is reformulated using a normalized time approach to cope with a free final time problem and boost time problem. Then, partial linearization and lossless convexification are used to convexify dynamic equation and control constraint, respectively. Finally, the results of the proposed method are compared with those of state-of-the-art nonlinear optimization method for verification.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.395-398
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• 2007

In nature, the swallowtail butterfly is known to be a versatile flyer using gliding and flapping efficiently. Furthermore, it has long tails on the hind-wing that may be associated with the enhancement of the gliding performance. In the present study, we investigate the aerodynamic property of swallowtail butterfly wing in gliding. We use an immersed boundary method and conduct a numerical simulation at the Reynolds numbers of 1,000 - 3,000 based on the free-stream velocity and the averaged chord length for seven different attack angles. As a result, we clearly identify the existence of the wing-tip and leading-edge vortices, and a pair of the streamwise vortices generated along the hind-wing tails. Interestingly, at the attack angle of $10^{\circ},$ hairpin vortices are generated above the center of the body and travel downstream.