• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.2
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• pp.257-264
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• 2015

This study is intended to provide navigator with specific information necessary to assist the avoidance of collision and the operation of ships to evaluate the maneuverability of dead weight tonnage 8,000 tons Oil/Chemical tanker. The actual maneuvering characteristics of ship can be adequately judged from the results of typical ship trials. Author carried out sea trials based full scale for turning test, Z" maneuvering test, man overboard rescue maneuver test, inertia stopping test. Consequently, $2^{st}$ Overshoot yaw angle of the semi balanced rudder and flap rudder in ${\pm}20^{\circ}$ zig-zag test showed $22.2^{\circ}$ and $18.0^{\circ}$, respectively. The maneuverability of the vessel was good in the flap rudder. The man overboard rescue maneuver maneuverability test was most favorable in the flap rudder and the full load condition. The results from tests could be compared directly with the standards of maneuverability of IMO and consequently the maneuvering qualities of the ship is full satisfied with its.

• Smart Structures and Systems
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• v.16 no.3
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• pp.555-577
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• 2015

In the work at hand, the development of a morphing flap, actuated through shape memory alloy load bearing elements, is described. Moving from aerodynamic specifications, prescribing the morphed shape enhancing the aerodynamic efficiency of the flap, a suitable actuation architecture was identified, able to affect the curvature. Each rib of the flap was split into three elastic elements, namely "cells", connected each others in serial way and providing the bending stiffness to the structure. The edges of each cell are linked to SMA elements, whose contraction induces rotation onto the cell itself with an increase of the local curvature of the flap airfoil. The cells are made of two metallic plates crossing each others to form a characteristic "X" configuration; a good flexibility and an acceptable stress concentration level was obtained non connecting the plates onto the crossing zone. After identifying the main design parameters of the structure (i.e. plates relative angle, thickness and depth, SMA length, cross section and connections to the cell) an optimization was performed, with the scope of enhancing the achievable rotation of the cell, its ability in absorbing the external aerodynamic loads and, at the same time, containing the stress level and the weight. The conceptual scheme of the architecture was then reinterpreted in view of a practical realization of the prototype. Implementation issues (SMA - cells connection and cells relative rotation to compensate the impressed inflection assuring the SMA pre-load) were considered. Through a detailed FE model the prototype morphing performance were investigated in presence of the most severe load conditions.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.520-525
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• 2003

A numerical investigation was performed to determine the effect of airfoil on the optimum flap height using NACA0015 Wells turbine. The five double flaps which have 0.5% chord height difference were selected. A Wavier-Stokes code, CFX-TASCflow, was used to calculate the flow field of the Wells turbine. The basic feature of the Wells turbine is that even though the cyclic airflow produces oscillating axial forces on the airfoil blades, the tangential force on the rotor is always in the same direction. Geometry used to define the 3-D numerical grid is based upon that of an experimental test rig. This paper tries to analyze the optimum double flap of Wells turbine with the numerical analysis.

• Archives of Reconstructive Microsurgery
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• v.15 no.2
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• pp.101-106
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• 2006

The purpose of this study was to analyze the mid to long-term clinical and radiological outcome of vascularized pronator quadratus-wrapped radial bone flap arthroplasty for symptomatic advanced $Kienb{\ddot{o}}ck's$ disease. Between 1982 and 2000, 41 cases of advanced $Kienb{\ddot{o}}ck's$ disease were treated with vascularized pronator quadratus wrapped radial bone flap arthroplasty. There were 17 men and 24 women, with a mean age of 39 years at the time of operation. According to Lichtman's classification, there were 13 stage IIIb and 28 stage IV patients. The duration of follow-up averaged 6.1 ($3{\sim}22$) years. We assessed the clinical outcome by subjective pain and active range of motion of the wrist, and evaluated the radiologic outcome by using carpal height ratio and radioscaphoid angle. Postoperatively, all patient reported an improvement in their symptoms. The mean active extension and flexion were improved by $9^{\circ}$ and $6^{\circ}$, respectively (p<0.05). The carpal height ratio was decreased from a mean of 0.52 to 0.48, and the radioscahpoid angle was increased from a mean of $61^{\circ}$ to $66^{\circ}$, but the differences were not significant statistically. Vascularized pronator quadratus-wrapped radial bone flap arthroplasty improves the wrist motion and may prevent serious carpal collapse in advanced $Kienb{\ddot{o}}ck's$ Disease.

• Archives of Plastic Surgery
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• v.43 no.6
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• pp.529-535
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• 2016

Background The trapezius muscle flap is not usually the first reconstructive option for skin and soft tissue defects in the posterior neck and scalp due to surgeons' unfamiliarity with the surgical anatomy and developments in free tissue transfer techniques. The goals of this study were to describe the clinical use of trapezius flaps in posterior neck and scalp reconstruction, and to investigate the vascular anatomy of trapezius flaps in Asians in order to obtain information facilitating the safe design and elevation of flaps in which most of the muscle is preserved. Methods A retrospective chart review was performed of 10 patients who underwent trapezius muscle flap for posterior neck and scalp defects. We also performed an anatomical study of 16 flaps harvested from 8 preserved Asian adult cadavers and evaluated the main landmarks relevant for trapezius muscle flap. Results In the anatomical study, the mean vertical height from the inferior angle of the scapula to the point at which the superficial cervical artery penetrated the trapezius was $4.31{\pm}2.14cm$. The mean vertical height of the trapezius muscle flap pivot point was $9.53{\pm}2.08cm$ from the external occipital protuberance. Among the 10 flaps, partial necrosis on the overlaid skin graft occurred in 1 patient and postoperative seroma occurred in another patient. Conclusions Vascular variations in the trapezius muscle flap are uncommon in Asians, but when present, such variations appear to have little impact on harvesting the flap or on its circulation. The trapezius muscle flap is a viable alternative for posterior neck and scalp reconstruction.

• Aerospace Engineering and Technology
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• v.9 no.1
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• pp.78-83
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• 2010

In the present paper, a flap was optimized to maximize the lift. A 2-element fowler flap system was utilized for optimization with an initial shape of general aviation airfoil and a flap shape designed by Wentz. Response surface method and Hicks-Henne shape function were implemented for optimization. 2-D Navier-Stokes method was used to solve flow field around aGA(W)-1 airfoil with a fowler flap. Commercial programs including Visual-Doc, Gambit/Tgridand Fluent were used. Upper surface shape and the flap gap were optimized and lift for landing condition was improved considerably. The original and optimized flaps were tested in the KARI's 1-m low speed wind tunnel to examine changes in aerodynamic characteristics. For optimized flap tests, the similar trend to prediction could be seen but stall angle of attack was lower than what was expected. Also, less gap than optimized design delayed stall and produced better lift characteristics. This is believed to be the effect of turbulence model.

• 한국전산유체공학회:학술대회논문집
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• 2011.05a
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• pp.441-446
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• 2011

To investigate aerodynamic performance of high-lift devices, 2D design is the base of the success of high-lift system design for transport aircraft, which can shorten the periods of three-dimensional design and analysis. For the simulation coupled viscous and inviscous euler method (MSES) is used. In this parametric study, Gap and Overlap which can define position of flap is used as design variables and we investigale relation between angle of attack and flap position for lift enhancement.

• Journal of the Society of Naval Architects of Korea
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• v.40 no.5
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• pp.10-16
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• 2003

To investigate the jet effect on circulation control, a segment of model was prepared and inserted horizontally across the test section of the cavitation tunnel. The hydrodynamic forces acting on the model were measured under the 2 dimensional flow behavior. Circulation flow control requires higher flow rate of water jet than boundary layer control does. Jet injection is effective in increasing lift coefficient and the increments reach to 160% in a certain combination of parameters such as an angle of attack, jet flow rate and flap angle. The blown water jet not only reduces form drag but also thrust effect, which is sometimes greater than the form drag in specific conditions.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.13 no.2
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• pp.14-26
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• 2005

A tilt-rotor aircraft has various flight modes : helicopter, airplane, and conversion. Each of flight mode has unique and nonlinear flight characteristics. Therefore the gain schedules for whole flight envelope are required for effective flight performance. This paper proposes collective, flap, and nacelle angle scheduler for whole flight envelope of the Smart UAV(Unmanned Air Vehicle) based on CAMRAD(Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics) II analysis results. The scheduler designs are improved so that the pitch attitude angle of helicopter mode was minimized. The range of scheduler are reduced inside of engine performance limits. The conversion corridor and rotor governor are suggested also.

• Journal of the Korean Society of Visualization
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• v.9 no.3
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• pp.30-37
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• 2011

The thrust vectoring concept has been used for use in new advanced supersonic aircraft. This study presents the performance characteristics of the thrust vectoring nozzle by visualizing the shock behaviors with Schlieren method. The scaled models were designed and manufactured to see the shock behaviors of the various airflow condition. Also we executed experimental tests to see the geometrical effects of the thrust vector nozzle by changing pitch angle and length of pitch flaps. From this study we could understand the supersonic flow characteristics of the thrust vector nozzle. The total thrust of thrust vector nozzle is diminished by increasing the flap angle. But there is an optimum flap length ratio for attaining the highest thrust level and proper pitch effect.