• 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.

• Archives of Reconstructive Microsurgery
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• v.5 no.1
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• pp.80-91
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• 1996

A free rectus abdominis flap can include a variable amount of muscle length depending on recipient site requirements. There is also great flexibility in flap design in terms of size, orientation of its axis, and the level of its location over the muscle. It is safe to design the skin island across the midline. Though skin islands designed over the most inferior portion of the abdomen have not always proved reliable when based on the superior epigastric artery, free flaps based on the inferior pedicle can be successfully designed in this area. As free flap based on the inferior epigastric vessels, this flap has been useful for large head and neck defects following ablative procedures, for facial contour restoration as a buried flap, for upper extremity defects, for lower extremity defects such as coverage of grade III tibial fractures and for breast reconstruction. A free rectus abdominis muscle or myocutaneus flap was used in 8 patients. The operations were performed between Sep. of 1994 and April of 1996. The patients were tongue cancer 1 case, chronic facial palsy 1 case, unilateral breast reconstruction 1 case, upper and lower extremity injury 5 cases. The free rectus abdominis muscle flaps were 4 cases and the free myocutaneous flaps were 4 cases. There was no failure of the flap, except one partial necrosis. One case of the skin grafts on the muscle flap was regrafted. One case of reoperation due to venous thrombosis was performed. In tongue cancer patient, a orocutaneous fistula was occurred, but conservative treatment and secondandry skin graft were done. In conclusion, a free rectus abdominis flap has many advantages such as a long and constant pedicle, easy dissection, enough soft tissue available, scar on the donor site to be hiddened, no need for changing position. So we think that this flap is the most useful one for small or moderate sized defects on the various sites.

• Archives of Plastic Surgery
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• v.50 no.6
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• pp.586-592
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• 2023

Background One-stage reconstruction with "thin perforator flaps" has been attempted to salvage limbs and restore function. The deep inferior epigastric perforator (DIEP) flap is a commonly utilized flap in breast reconstruction (BR). The purpose of this study is to present the versatility of DIEP flaps for the reconstruction of large defects of the extremities. Methods Patients with large tissue defects on extremities who were treated with thin DIEP flaps from January 2016 to January 2018 were included. They were minimally followed up for 36 months. We analyzed the etiology and location of the soft tissue defect, flap design, anastomosis type, outcome, and complications. We also considered the technical differences in the DIEP flap between breast and extremity reconstruction. Results Overall, six free DIEP flaps were included in the study. The flap size ranged from 15 × 12 to 30 × 16 cm². All flaps were transversely designed similar to a traditional BR design. Three flaps were elevated with two perforators. Primary closure of the donor site was possible in all cases. Five flaps survived with no complications. However, partial necrosis occurred in one flap. Conclusion A DIEP flap is not the first choice for soft tissue defects, but it should be considered for one-stage reconstruction of large defects when the circulation zone of the DIEP flap is considered. In addition, this flap has many advantages over other flaps such as provision of the largest skin paddle, low donor site morbidity with a concealed scar, versatile supercharging technique, and a long pedicle.

• Advances in aircraft and spacecraft science
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• v.2 no.3
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• pp.329-343
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• 2015

This study aimed to observe the effect of a novel concept (referred to as the flap extension) implemented on the leading edge of the flap of a three element high lift device. The high lift device, consisting of a flap, main element and slat is designed around an Airbus research profile for sufficient take off and landing performance of a large commercial aircraft. The concept is realised on the profile and numerically optimised to achieve an optimum geometry. Two different optimisation approaches based on Genetic Algorithm optimisations are used: a zero order approach which makes simplifying assumptions to achieve an optimised solution: as well as a direct approach which employs an optimisation in ANSYS DesignXplorer using RANS calculations. Both methods converge to different optimised solutions due to simplifying assumptions. The solution to the zero order optimisation showed a decreased stall angle and decreased maximum lift coefficient against angle of attack due to early stall onset at the flap. The DesignXplorer optimised solution matched that of the baseline solution very closely. The concept was seen to increase lift locally at the flap for both optimisation methods.

• The Journal of the Korean dental association
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• v.48 no.8
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• pp.607-614
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• 2010

Reconstruction after ablative oral cancer surgery is challenging mission. Soft tissue and hard tissue could be resected in case of advanced oral cancer. The final goal of oral reconstruction is to gain normal swallowing, chewing and speech. Nowadays, free flap reconstruction after oral cancer resection is more popular than pedicled flap. Microsurgical reconstruction with free flap could be used effectively in complicated cases of oral cavity defect. However, complications could be happened. So not only meticulous preoperative study about the extent of defects but also the donor site dressing after surgery were performed to prevent postoperative complication. The most favorite free flap for soft tissue reconstruction is radial forearm flap. It has a lot of advantages such as pliable, hairless, reliable vessels, appropriate diameter of radial artery and diverse flap design. And the most popular free flap for jaw reconstruction is free fibular flap. In this article, we report the classification of flap for reconstruction and reveal the pits and falls of radial forearm free flap and free fibular flap.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.7
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• pp.542-550
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• 2018

This paper presents design of a bearingless main rotor of SNUF (Seoul National University Flap) blade equipped with active trailing-edge flap to reduce the hub vibratory loads during helicopter forward flight. For that purpose, sectional design of the flexbeam is carried out using the thin-walled composite material rotating beam vibration analysis program (CORBA77_MEMB) in EDISON. Using the multi-body dynamics analysis program, DYMORE, blade dynamic characteristics and those of the loads control are examined using the active trailing-edge flap in terms of the flexbeam sectional design.

• Korean Journal of Head & Neck Oncology
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• v.21 no.2
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• pp.190-195
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• 2005

Background and Objectives: Fibula is the flap of choice for reconstruction of wide mandible defects after tumor ablation surgery. In mandible reconstruction, restoring the mandible frame to provide mandibular contour and dental arch while restoring masticatory function are important. Even though vascularized fibula can be osteotomized freely, proper design and flap insetting is not easy because of its three dimensional structure and difference in design according to the defect sites. We reviewed patients who underwent mandible reconstruction with fibular flaps according to the defect sites and suggest proper modification methods of fibular flap according to the various defects sites after tumor ablation surgery. Materials and Methods: Twelve consecutive mandible reconstruction with fibular free flaps were performed for defects after tumor ablation surgery. Patients were classified into 4 groups according to the type of mandibular defect(Group 1 : defect on central segment including symphysis, Group 2 : defect on lateral segment(with or without central segment) confined to body, Group 3 : defect on body and ascending ramus that does not include the condyle, Group 4 : defect including the condyle). Results: We suggest different modification methods of fibular free flap for each patient group. Group 1, 3 ; contour by using multiple closing wedge osteotomy. Group 2 ; single or double barrel reconstruction without wedge osteotomy. Group 4 ; contour using single or multiple wedge osteotomy and condylar reconstruction with costochondral graft. Conclusion: Fibular free flaps can be contoured to any desired shape after multiple osteotomies to restore various mandibular defects. It is a reliable and versatile method for reconstruction of mandibular defects after tumor ablation surgery.

• International Journal of Aerospace System Engineering
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• v.4 no.1
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• pp.13-21
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• 2017

In this paper, we present some results on performance analysis for flap actuation system of aircraft. For this, by utilizing MATLAB/Simulink solution, which is widely used physical model-based design tool, we particularly construct the architecture of the analysis model consisting of the main three phases: 1)commanding and outer-controlling the flap angle through flight control computer; 2)generating hydraulic/mechanical power through control module and power drive unit; 3)transmitting torque and actuating the flap through torque tube and rotary geared actuators. For mimicking the motion of the actual flap, we apply each mechanical component, which is already being used in actual aircraft, to our performance analysis model so that it guarantees the congruency of the simulation results. That is, we reflect the actual specifications of flap hardware and software as parameters of the model. Finally, simulation results are presented to illustrate the model.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.35-40
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• 2005

Maneuverability of ships has been receiving a great deal of attention both concerning navigation safety and the prediction of ship maneuvering characteristics, to improve it. high-lift device could be applied to design of rudder at design stage. Now, we carried out the flow visualization and investigation of flow field around a flap rudder(trailing-edge flap). Flow visualization results of flap defection shown as the flow around a NACA0020 Flap Rudder will be conducted in a Circulating Water Channel. The purpose of this investigation will be to investigate the development of the separation region on the flap rudder with the variation of the angle of attack and determine the angle of attack at which the flow separates and reattaches.

• Ocean and Polar Research
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• v.42 no.4
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• pp.293-301
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• 2020

Blades of tidal stream turbines have to sustain many different loads during operation in the underwater environment, so securing their structural safety is a key issue. In this study, we focused on periodic loads due to wave orbital motion and propose a load reduction method with a blade design. The flap of an airplane wing is a well-known structure designed to increase lift, and it can also change the load distribution on the wing through deflection. For this reason, we adopted a passive flap structure for the load reduction and investigated its effectiveness by an analytical method based on the blade element moment theory. Flap torsional stiffness required for the design of the passive flap can be obtained by calculating the flap moment based on the analytic method. Comparison between a flapped and a fixed blade showed the effect of the flap on load reduction in a high amplitude wave condition.