• Journal of the Korean Society of Marine Environment & Safety
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• v.21 no.2
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• pp.200-206
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• 2015

In order to verify the lift enhancement of the 2D hydrofoil with trailing edge rotor and check the ability of its practical use, experimental studies were conducted in the caviation tunnel using the test model with NACA0020 section. The three-component forces acting on the model could be measured by exclusively designed sting type multi-component load cell. The trailing edge of the model has been replaced with rotor which could be controlled by DC servo motor installed at the exterior of the tunnel. A typical effect of the trailing edge rotor has been introduced among the systematic experiments on various angular deviation of the model and the rotational velocity of the trailing edge rotor. It is appeared that the circulation control effect could be easily adjusted by selecting the rotational velocity of the trailing edge rotor and the lift force was augmented more than two times. Thus the proposed lifting device could be utilized as a novel high lifting device which has adjustability of lift force.

• Conservation Science in Museum
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• v.23
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• pp.71-90
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• 2020

The scientific analysis of a 'F-51D Mustang Fighter'(Registered Cultural Heritage 666), one of the War Memorial of Korean collections, was carried out. The paint layer and canopy were discolored due to a constant outdoor exhibit. The results obtained through the scientific survey and analysis processes were intended to be used as basic data for the future dismantling and restoration of the fighter. The analysis results for the pigment components have confirmed red oxide of iron, Fe₂O₃ organic pigments, such as Cobalt Blue, phthalocyanine blue, etc., yellow PbCrO₄, white TiO₂, black Fe₃O₄, and gray Fe₃O₄ + TiO₂. It has been also confirmed that Alkyd resin was mainly used for painting. The fighter's canopy was Poly methyl methacrylate(PMMA), and Al was detected as the main component of the fighter body, wings, and tails.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.7
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• pp.1-12
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• 2004

A flow visualization of the 1st cycle motion of a fling-clapping wing that might be employed by butterflies during flight is performed. In this numerical flow visualization, he time-dependent Navier-Stokes equations are solved for two wing motion types; 'fling followed by clap and pause' and 'clap followed by fling and pause'. The result is observed regarding the main flow features such as the sequential development of the two families of separation vortex pairs and their movement. For the fling followed by clap and pause motion, a strong separation vortex pair of counter-clockwise develops in the opening between the wings in the fling phase and they then move out from the opening in the following clap phase. For the clap followed by fling and pause motion, the separation vortex pair developed in the outside space in the clap phase move into the opening in the following fling phase. The separation vortex pair in the opening developed in the fling phase of the clap followed by fling and pause motion is observed to be stronger than that in the opening developed in the fling phase of the fling followed by clap and pause motion.

• Journal of Aerospace System Engineering
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• v.16 no.3
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• pp.99-104
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• 2022

Aircraft pylon connects the engine or external stores to the main wing, and transfers the load acting on the pylon to the main structure of the aircraft. In particular, it should perform the function of separating the external store mounted on the pylon in case of emergency or mission performance. At this time, if the separation of the external store is not performed properly due to peripheral air flow or functional problems during the separation process of the external store, it may seriously impact the survivability of the aircraft. For this reason, to apply an external attachment to an aircraft, it is necessary to prove the stability of the external attachment in the separation situation in advance. In this paper, we present the result of the ground separation test performed to confirm that the external fuel tank, which is an external attachment, can be safely separated from the pylon. As a result of the test, the separation movement of the external fuel tank was measured with a high-speed camera, and the stability of the separation of the external fuel tank from the pylon were confirmed through the ground separation test. Additionally, the test result provides basic data for the stability evaluation of the separation of external attachments in actual aircraft.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.1-8
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• 2004

In this study, the method of computing and extracting the generalized unsteady aerodynamic matrices using MSC/NASTRAN and MSC/NASTRAN DMAP ALTER has been suggested for the analysis and control of aeroelastic phenomena such as flutter and gust response analysis. In addition to that, the method of approximating the generalized unsteady aerodynamic matrices using minimum state approximation method has been proposed in order to cast the aeroelastic equations of motion in state space form for aeroelastic analysis and control application. Simplified aircraft wing box model has been used for the validation of the methods suggested in this study.

• Journal of the Korea Institute of Military Science and Technology
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• v.10 no.4
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• pp.73-80
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• 2007

Modern aircraft are required to carry various external stores mounted at different locations on the wing. Sometimes the attachment of stores to an aircraft wing leads to flutter speed reduction, which is a very severe aeroelastic problem. In order to suppress structural vibration and expand the flutter boundary of the aircraft with stores, it is necessary to investigate the main problems and characteristics of them. In addition, active vibration control may be required because passive vibration isolators show limited capabilities for the various wing/store configuration. In this paper, therefore, the flutter stability to the various wing/store configurations was investigated and active vibration control of wing/store model was performed using a piezoelectric actuator.

• Animal Systematics, Evolution and Diversity
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• v.15 no.1
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• pp.27-49
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• 1999

Thirteen species of Limnephilidae and two of Goeridae are recorded from South Korea. Among them, Brachypsyche schmidi, is described as new to science, and Limnephilus orientalis Martynov and Goera curvispina Martynov are reported for the first time from the Korean peninsula. In addition, Nemotalius mutatus MacLachlan, Asynarchus amurensis Ulmer, and Hydatophylax formosus Schmid are recognized as new to South Korean fauna. Diagnostic information with illustrations fo adults, genitalia of both sexes, and distribution data are provided.

• KOREAN POULTRY JOURNAL
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• v.25 no.9 s.287
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• pp.119-123
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• 1993

요즈음 날씨같이 낮에는 전형적인 혹서기를 나타내나 밤이되면 썰렁해져서 자다가도 이불을 찾게 되는데 이런 경우 병아리는 어떤 영향을 받게될까? 병아리날개는 피부보다도 더 예민하여 저온 스트레스를 받게되면 금방 흉터가 생기게 되며 이는 환우를 할때까지 없어지지 않는다. 또한 복부를 덮고 있는 피부는 종이같이 얇으며, 자체 체온조절기능이 미숙하여 외부의 기온영향을 장기에 바로 받게된다. 번개가 치고 난 이후 변압기 등이 손상되었을때 폐사가 많이 나는 이유도 이런데 있는 것이다. 온도관리가 그만큼 중요하다는 이야기이며 성장과도 직결되는 문제이다. 그러나 계절차이, 일교차, 수용시설, 수용수수 과다 등으로 실제 온도관리는 어려움도 많이 따르며 제대로 되지 않는 경우도 많이 볼 수가 있다. 더군다나 요즘같은 날씨에서는 더욱더 그러하다. 병아리는 입추 후 어느 일령에 다다르면 원래 가지고 있던 솜털을 벗으면서 첫번째 환우를 하게되는데 이것으로 병아리 상태파악과 관리에 응용할 수 있는 방법은 없을까?

• Korean journal of applied entomology
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• v.56 no.4
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• pp.435-436
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• 2017

Subgena and clypeus are a continuous plate, so should be collectively called as peristoma. Subsequently, subgenal sulcus is revised into peristomal sulcus or cranio-stomal sulcus. Ptilinal suture on dipteran adult head is revised into ptilinal fissure. Notal and pleural wing processes are revised into notal and pleural process, respectively. The lower plate of abdomen is ventum, while that of thorax is sternum.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1995.11a
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• pp.159-167
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• 1995

본 연구는 유도탄 비행시험시에 연소관의 스커트와 날개 장착용 브라켓에 작용하는 공력하중과 연소관에 내압이 동시에 작용하는 추진기관에 대하여 구조 해석하였다. 추진기관의 스커트부 및 브라켓부의 공력하중은 3차원적으로 작용하기 때문에 대칭성을 이용한 $180^{\circ}C$3차원 구조 해석을 수행하여 비행시험, 수압시험, 지상시험 모드에 대하여 응력 수준을 비교하였다. 해석 결과 3가지 모드의 최대 등가응력은 거의 같으며, 비행시험시 공력하중이 앞마개부에 미치는 영향은 최대 등 가응력의 6%이내로 상당히 작았다. 수압시험 모드와 지상시험 모드의 실험치와 해석치를 비교한 결과 정확한 해석을 위해서는 점화기를 모델링과 점화기와 연소관, 브라켓과 연소관에 접촉요소의 적용, 3차원 비선형 해석등 보다 상세한 해석이 필요함을 알 수 있었다.