• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.227-228
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• 2008

In the present paper, fowler flap was optimized to maximize the lift with response surface method. Leading edge shape and the gap between main airfoil and flap, were optimized and the aerodynamic characteristics was improved considerably. The optimized flap has more rounded leading edge and bigger gap. Before angle of attack, $10^{\circ}$, lift and drag are improved and the optimized flap shows similar aerodynamic characteristics to the original flap. The flow condition for optimization was angle of attack, $10^{\circ}$, Mach number, 0.2, flap deflection, $40^{\circ}$.

• Archives of Reconstructive Microsurgery
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• v.6 no.1
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• pp.80-86
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• 1997

The lateral arm flap was reported first by Song et al. in 1982, and Katsaros and colleagues described an anatomic study and clinical cases in 1984. This flap is thin, has relatively constant vascular anatomy, and provides relatively acceptable scar at the donor site. Despite its many advantages its wide application has been limited by its short vascular pedicle with small diameter of lumen, and its small skin paddle. We studied its anatomical structure to get longer length of vascular pedicle, wide diameter and thinner part of flap beyond the lateral condyle through 6 fresh cadaver dissection and dye injection study. We experienced 21 cases of lateral arm free flaps and 26 cases of forearm free flaps from May, 1992 to January, 1996. We compared its usefulness with forearm free flaps in the aspects of donor morbidity, operative factors, quality of flap, and versatility. In conclusion, lateral arm flap can replace the role of forearm flap in most cases so that patient's donor morbidity can be reduced especially in the women.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.916-921
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• 2014

In this paper, an improved small-scaled blade prototype was designed with the flap-driving mechanism classified as an active vibration reduction method, in order to reduce vibratory load in the helicopter. In detail, the previous Active Trailing-Edge Flap based on piezoelectric actuator, called SNUF(Seoul National University Flap), failed to achieve the target value (${\pm}4^{\circ}$) of the flap deflection angle. Therefore, the flap-driving mechanism design was improved, and a new piezoactuator was selected to accomplish the target value of the flap deflection angle in both static and rotating situations.

• Journal of Industrial Technology
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• v.20 no.B
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• pp.71-76
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• 2000

A numerical investigation was performed to determine the effect of the Gurney flap on NACA 0015 airfoil. A Navier-Stokes code. FLUENT, was used to calculate the flow field about the airfoil. The fully-turbulent results were obtained using the standard ${\kappa}-{\varepsilon}$ two-equation turbulence model. The numerical solutions showed the Gurney flap increased both lift and drag. These results suggested that the Gurney flap served to increase the effective camber of the airfoil. Gurney flap provided a significant increase in lift-to-drag ratio relatively at low angle of attack and for high lift coefficient. It turned out that 0.75% chord size of flap was best. The numerical results exhibited detailed flow structures at the trailing edge and provided a possible explanation for the increased aerodynamic performance.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.13 no.3
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• pp.305-318
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• 1991

Reconstructive techniques of orofacial defects are very varied. In recent years, myocutaneous flaps, in particular the pectoralis major or latissimus doris myocutaneous flap have achieved popularity. In 1983, Soutar et. al. used the forearm free flap that had been developed in in China and popularised the radial forearm fasciocutaneous flap to reconstruct defects in the orofacial region. This paper presents the authors experience with 10 consecutive patients in which 12 flaps were used either as a fascioncutaneous flap or as a composite flap incorporating part of the radius. Some literatures were reviewed and the clinical results were discussed.

• Journal of Industrial Technology
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• v.18
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• pp.335-341
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• 1998

A numerical investigation was performed to determine the effect of a Gurney flap on a NACA 23012 airfoil. A Navier-Stokes code, RAMPANT, was used to calculate the flow field about airfoil. The fully turbulent results were obtained using the standard $k-{\varepsilon}$ two-equation turbulence model. To provide a check case for our computational method, computations were performed for NACA 4412 airfoil which compared with Wedcock's experimental data. Gurney flap sizes of 0.5, 1.0, 1.5, and 2% of the airfoil chord were studied. The numerical solutions showed the Gurney flap increased both lift and drag. These results suggested that the Gurney flap served to increased the effective camber of the airfoil. But Gurney flap provided a significant increase in lift-to-drag ratio relatively at low angle of attack and for high lift coefficient. Also, it turned out that 0.5% chord size of flap was best one among them.

• 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.

• Archives of Plastic Surgery
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• v.51 no.1
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• pp.126-129
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• 2024

The square flap method has been successful in releasing contracture bands at various body regions. However, the original square flap method alone may not be efficient in releasing long contracture bands. We, therefore, proposed an extended design to the traditional design, which is called the "square-plus flap." A 4-year-old girl presented with a postburn web-like contracture band over the right axilla. We marked a square flap technique at the center of the contracture band and then two additional Z-plasties were placed on both edges of the flap. After the release and securing of the square flap, the adjacent distal Z-plasty was then transposed and sutured in their new locations. We do not need to incise the proximal Z-plasty as we could achieve complete relaxation of the contracture band. This novel modification can be added to the plastic surgeon's armamentarium for releasing long postburn contracture bands involving distinct body regions.

• Archives of Reconstructive Microsurgery
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• v.11 no.1
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• pp.11-18
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• 2002

Large soft tissue defects around the knee joint are known to significantly diminish joint function. Severe soft tissue defects on the anterior aspect of the knee joint especially bring on significant joint motion limitation. Although simple split skin grafts can cover the skin defect, the progressing scar contracture of the grafted skin causes joint stiffness. One of the best solutions of large soft tissue defects around the knee joint is covering the defect with a good quality skin flap. Separated flaps with one vascular pedicle are good candidates for covering anterior and posterior aspects of the joint for example. Authors performed 12 cases of combined scapular and latissimus dorsi free flaps from 1984 to 2000. Among them, we experienced 5 cases of knee joint defect covering using the double free flap for coverage of the soft tissue defect with preservation of the knee joint function and satisfactory results. The system of flaps based on the subscapular artery and vein provides a variety of composite free flaps. The possible flaps that can be harvested based on this single vascular pedicle include the scapular and parascapular skin flap, the serratus anterior and latissimus dorsi muscular flap, the lateral scapular bone flap, the latissimus dorsi-rib flap, and the serratus anterior-rib flap. This combined flap is available for multiple tissue defects or complex defects because it can be incorporated with skin, muscle and bone flaps. A main advantage is the independent vascular pedicles of each component, which allow freedom in orientation of each components. Consequently it can be freely applied to any form of three dimensional defects on the upper and lower extremities. The combination of scapular cutaneous flap and latissimus dorsi musculocutaneous flap can be resurfaced for massive cutaneous defects on the extremities. We report the use of the combined scapular and latissimus dorsi free flap in five patients to reconstruct massive defects on the extremities with resultant improved joint function. There was no flap failure and minimal complications and disadvantages. The anatomy of this flap is reviewed and the indication and advantages are discussed. All of the five flaps survived and there was no scar contracture affecting the joint motion.

• Archives of Reconstructive Microsurgery
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• v.8 no.1
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• pp.35-43
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• 1999

There are lots of reconstructive ways like direct closure, skin graft, local flap, regional flap, distant flap, free flap and so on. Microsurgical reconstruction is regarded as the last step in various reconstructive methods. So the failure of this last step causes the troublesome situation for both of patients and surgeon. The purpose of this paper is to investigate the problems in failed free flap surgery and to introduce the strategy of appropriate management in wound of free flap failure. We performed 252 cases of free flap surgeries from May, 1988 to June, 1998. Among these cases, we failed 9 cases of free flaps. Patients' age ranged from 19 to 63. There were 7 males and 2 females. Site of failure were 3 head and neck areas, 2 hands, and 4 lower extremities. However there was no failure in breast, trunk, buttock, and genitalia. 7 patients who had region of head and neck, and lower extremity underwent the second free flap surgery successfully in postoperative 4 to 16 days following debridement of necrotic tissue. However 2 patients who had region in hand were managed with conventional treatment like skin graft and distant flap. Vein grafts were needed in 3 cases of 7 second free flaps, and 1 patients needed sequentially-linked free flaps with two flaps. The second free flaps were inevitable for head and neck area because the large complex wound may cause the lifethreatening condition without immediate coverage with well vascularized flap. Lower extremity also needed second free flap for limb salvage. Hand could be managed with conventional method, even though healing time was quite delayed. We thought second free flap surgery in free flap failure cases should be performed with more careful preoperative evaluation and refined surgery. Success of second free flap surgery could recover the very difficult situation due to previously failed operation.