• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.299-304
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• 2013

초음속 조건에서 Busemann biplane은 충격파의 중첩에 의해 항력 감소가 일어난다. 그러나 받음각이 증가 할 경우, 앞전에서 궁형 충격파가 발생하여 항력이 급격하게 증가한다. 이에 본 연구에서는 busemann biplane에 플랩을 주어 궁형 충격파를 감소시킬 수 있는 flap biplane의 플랩 길이와 각도의 변화에 따른 공력 성능의 변화를 분석하였다. Flap biplane의 공력성능을 기본 biplane형상 및 diamond airfoil과 비교한 결과, 동일한 양력 조건에서 항력은 diamond airfoil에 비해 약 75%정도 감소함을 확인하였다. 그리고 플랩의 길이와 양항비는 선형의 관계가 있음을 확인하였고, 특정한 플랩의 각도에서 최대 양항비가 도출된다는 사실을 확인하였다. 마지막으로 전압력의 감소를 충격파의 강도로 정의하고, 이를 비교한 결과 flap biplane의 전압력 감소가 diamond airfoil에 비해 약 25%정도가 더 작게 나타난 사실로 부터 flap biplane의 소음 감소 효과를 유추할 수 있었다. flap biplane은 초음속 영역에서 항력과 소음의 감소에 효율적인 익형임을 확인하였다.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.42-50
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• 2013

The supersonic airplane with flapped biplane, Busemann biplane equipped flap, is superior to drag and noise reduction due to wave cancelation effect between upper and lower airfoils. In this study, it is numerically calculated and analyzed the lift, drag and lift to drag ratio of flapped biplane with respect to various the length and angle of the flap. Euler solver of EDISON CFD, web based computational fluid dynamic solver for the purpose of education, is employed. Depending on the length of the flap, lift and drag increase linearly, and there exists the optimum flap angle which maximize the lift-to-drag ratio at the freestream mach 2.0 on-design condition. The predictable relational expression is driven as liner equation. As a results of comparison with drag of flapped biplane, Busemann biplane, and diamond airfoil with the same lift, the drag of flapped biplane is 88.76% lower than that of the Busemann biplane and 70.67% lower than that of the diamond airfoil. In addition, the change of pressure is compared to confirm the noise reduction effect of flapped biplane at h/c=5 of lower airfoil. The shock strength of flapped biplane is smaller than that of other airfoils.

• The Korean Journal of Pain
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• v.18 no.2
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• pp.279-283
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• 2005

Biplane fluoroscopy is usually used in angiography. Biplane fluoroscopy gives a biplane image with high resolution during the performance of operations. Trigeminal nerve blocks are effective treatment modalities for trigeminal neuralgia, and maxillary nerve block is the most dangerous procedure among them. The anatomic structures can change after head and neck surgery, so the trigeminal nerve block procedures cannot be done so easily. We used biplane fluoroscopy in these difficult cases. Our first case was a 60-year-old man who had undergone maxillary nerve block. The second case was of a 64-year-old man who had pulsed radiofrequency lesioning of mandibular nerve performed after head and neck surgery. With biplane fluoroscopy, we got good results without any complications.

• International Journal of Aeronautical and Space Sciences
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• v.14 no.3
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• pp.229-236
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• 2013

This paper presents the experimental investigation of a biplane micro air vehicle. The effects of geometric parameters, gap, stagger, and decalage angle are investigated at low Reynolds number (~150,000) in a low-speed wind tunnel. A rigid flat plate with an aspect ratio of one and square planform shape is used to evaluate all three geometric parameters. The side dimension of the single flat plate is 0.15 m. The goal is to find an optimal biplane configuration that should exceed monoplane performance by generating high lift and flying as slow as possible, in order to capture high-quality visual recordings. This configuration will directly help to fly at a lower velocity and to make tighter turns that are advantageous in restricted environments. The results show that the aerodynamic performance of the biplane MAV is significantly enhanced through the combination of gap and stagger effects. A performance comparison demonstrates the superiority of the optimal biplane configuration compared to a monoplane in cruise and glide phases. Moreover, no significant compromise is found for the range, endurance, and climb performance.

• Journal of the Korean Society for Precision Engineering
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• v.30 no.6
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• pp.601-606
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• 2013

3D scanning is a technique to measure the 3D shape information of the object. Shape information obtained by 3D scanning is expressed either as point cloud or as polygon mesh type data that can be widely used in various areas such as reverse engineering and quality inspection. 3D scanning should be performed as accurate as possible since the scanned data is highly required to detect the features on an object in order to scan the shape of the object more precisely. In this study, we propose the method on finding the location of feature more accurately, based on the extended Biplane SNAKE with global optimization. In each iteration, we project the feature lines obtained by the extended Biplane SNAKE into each image plane and move the feature lines to the features on each image. We have applied this approach to real models to verify the proposed optimization algorithm.

• Journal of Chest Surgery
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• v.18 no.1
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• pp.19-23
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• 1985

There are several factors influencing post-operative mortality in Tetralogy of Fallot, such as degree of RV outflow tract obstruction, combined anomaly, and age of the patient. Another factor is preoperative left ventricular volume reported by Kirklin and Graham in 1978. From March to September, 1984, 10 patient with Tetralogy of Fallot have been taken biplane cinecardioangiography [LAO and RAO projection] for measuring left ventricular volume by area-length method. The mean age of the patients was 84.9 [S.D.] and 3 males and 7 females were there. Mean value of left ventricle was 62.9ml/m2, which was no statistically difference from normal value. [p value=0.08]. In conclusion, though this study suggests that there is some decrease of left ventricular end-diastolic volume in Tetralogy of Fallot preoperatively as compared with normal individuals, further evaluation is needed to make it confirmatory with more number of patients and lesser range of age of the patients submitted to the study.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.365-370
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• 2013

현대에 이르러 초음속 운영 영역에서의 항공기에 대한 많은 연구가 진행되고 있으나, 음속 폭음 현상과 충격파 현상에서 야기된 높은 항력 및 연료 효율성 저하로 인하여 그 한계에 부딪치고 있다. Busemann 복엽 익형은 이와 같은 문제를 해결하기 위한 형상이며, 상하 형상에 의한 파동 상쇄효과 및 파동 감소효과를 통해 충격파의 강도와 음속 폭음 효과를 감소시키는 형상이다. 하지만 본 익형은 탈설계 조건에서 항력 계수가 급격하게 증가하는 등의 문제점을 가지고 있다. 본 연구에서는 EDISON_CFD를 이용하여 Busemann 복엽 익형의 주변 유동 특성에 대하여 면밀한 고찰을 수행하였다. 우선 Busemann 복엽 익형의 초기 형상에 대한 유동 조건별 해석을 통하여 탈설계 조건에서의 항력 성능 저하 문제에 대한 고찰을 하였다. 이후 3개의 형상 변수에 대한 매개 변수 연구를 통하여 익형의 각 형상 변수가 탈설계 영역 및 해당 영역에서의 최대 항력 계수에 미치는 영향에 대한 고찰을 수행하였으며, 이를 통하여 기존 형상보다 좁은 탈설계 구간을 가지고, 최대 항력 계수가 약 34.8% 감소한 부스만 복엽 익형을 설계하였다.

• 순환기질환의공학회:학술대회논문집
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• 2003.11a
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• pp.8-9
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• 2003

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.9-17
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• 2005

The wake patterns and thrust characteristics of dual flapping airfoils in a biplane configuration are investigated using an unsteady panel method. To trace complicated wake shapes behind airfoils, a core addition scheme, a vortex core model, and the fourth order Runge-Kutta convection scheme are employed. Present results are verified by comparing them with flow visualization, exact solution and published computed results. The thickness and camber of thick airfoils has an effect of decreasing thrust. The airfoils produce maximum thrust when the phase angles between plunging and pitching motions are both 90 and 120 degrees. Thrust increases as the plunge velocity is increased, which is also found as the pitch amplitude is stepped up. Thrust decreases when the distance between the airfoils is less than 0.6c.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.415-420
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• 2007

Creatures in nature flap their wings to generate fluid dynamic forces that are required for the locomotion. Small-size creatures do not use flapping wings. Thus, it is questionable at which Reynolds number the propulsion using the flapping wings are effective. In this paper, the onset conditions of the thrust generation from the combined motion of flat plates (heaving, pitching in the motion and also tandem, biplane in the array) is investigated using a Lattice Boltzmann method. To solve the pitching motion of the plate on the regularly spaced lattices, 2-D moving boundary condition was implemented. The present method is validated by comparing the wake patterns behind a oscillating circular cylinder and its hydrodynamic characteristics with the CFD results. Present method can be applied to the design of micro flapping propulsors for biomedical use.