• 한국전산유체공학회:학술대회논문집
• /
• 2000.10a
• /
• pp.32-38
• /
• 2000

Wing flap deflection angles of a supersonic transport are optimized to improve transonic cruise performance. For this end, a numerical optimization method is adopted using a three-dimensional unstructured Euler code and a discrete adjoint code. Deflection angles of ten flaps; five for leading edge and five fur railing edge, are employed as design variables. The elliptic equation method is adopted for the interior grid modification during the design process. Interior grid sensitivities are neglected for efficiency. Also tested is the validity of the approximate gradient evaluation method for the present design problem and found that it is applicable for loading edge flap design in cases of no shock waves on the wing surface. The BFGS method is used to minimize the drag with constraints on the lift and upper surface Mach numbers. Two design examples are conducted; one is leading edge flap design, and the other is simultaneous design of leading edge and trailing edge flaps. The latter gave a smaller drag than the former by about two counts.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.38
• /
• pp.10.1-10.5
• /
• 2016

Herniation after harvesting of deep circumflex iliac artery (DCIA) flap is a known but not a common complication. It occurs about 2.8 to 9 % according to the literatures and can proceed to a more severe complication such as bowel obstruction. There are several factors that exacerbate the risk: surgical factors, operator factor, and patient factors. Surgical factors include large anatomical defect and denervation of related muscles. Operator factor stands for unpunctual suture technique. Patient factors represent obesity, diabetes, pulmonary disease, smoking habits, and so on. Thus, herniation might occur regardless of meticulous suture. Herein, we would like to report two cases of herniation after DCIA flap harvesting and repaired by Lichtenstein tension-free hernioplasty with literature review.

• Archives of Reconstructive Microsurgery
• /
• v.14 no.1
• /
• pp.14-17
• /
• 2005

Purpose: Authors have performed free tissue transplantation in the upper and lower extremities with sensory flaps and evaluated the sensory function recovery. Materials and methods: Between 1992 through 2004, sensory free flap articles published in the journal of the Korean microsurgical society, were reviewed and recovery of sensory function was assessed by static two-point discrimination test. Results: Static two point discrimination test showed average 6.7 mm in the thumb, average 12 mm in the hand and 7 cm of the dorsalis pedis flap, 20.5 mm of the lateral arm flap and over 8 cm of the forearm flap in the foot. Conclusion: Sensory flaps provide the protective and useful coverage in the upper and lower extremities and have benefit for activities for daily life in free tissue transferred patients.

• Archives of Reconstructive Microsurgery
• /
• v.10 no.1
• /
• pp.60-63
• /
• 2001

The reconstruction of the suborbital area followed by resection of skin cancer has been used many methods including skin graft, local flaps, free flaps, and skin expansion. The radial forearm free flap has become a workhorse flap in this area because of its lack of bulk, ease of dissection, malleability, and hairlessness. When the suborbital defect especially including full-thickness defect of lower lid was reconstructed with many free flaps, the ectropion and the deformity of medial and lateral canthal area were common problems encountered as late complication due to gravitational descent. To improve the final aesthetic result in patients with suborbital defect, the radial forearm free flap was elevated as a composite radial forearm - palmaris longus free flap, in which the vascularized palmaris longus london was included and anchored to the periorbital bone with $mitek^{(R)}$ as sling, to suspend the flap against gravity and inferior descent, and thereby creating a more natural cheek contour. Two clinical cases were presented as an example of this procedure. Postoperative results emphasize the importance of suspension sling with palmaris longus tendon using $mitek^{(R)}$ in reconstruction of the suborbital defect with radial forearm free flap.

• Archives of Reconstructive Microsurgery
• /
• v.5 no.1
• /
• pp.56-61
• /
• 1996

The nasal ala and columella represent a difficult location for reconstruction, especially when defect area is covered with scar. Local flap, such as forehead flap or nasolabial flap, may result in additional facial scarring and bulkiness that require multiple thinning revisions. Recent delineation of vascular territories of the ear has allowed the use of vascularized auricular free flap in the reconstruction of large ala and columella defects. Authors reconstructed two cases of full thickiness defect of the ala and columella with auricular free flap. The pedicle of this flap is the superficial temporal artery and vein. The donor vessels were anastomosed to the facial artery and vein. The results were satisfactory cosmetically and functionally.

• Advances in aircraft and spacecraft science
• /
• v.2 no.1
• /
• pp.45-56
• /
• 2015

The attitude aerodynamic control is an important subject in the design of an aerospace plane. Usually, at high altitudes, this control is fulfilled by thrusters so that the implementation of an aerodynamic control of the vehicle has the advantage of reducing the amount of thrusters fuel to be loaded on board. In the present paper, the efficiency of a wing-flap has been evaluated considering a NACA 0010 airfoil with a trailing edge flap of length equal to 35% of the chord. Computational tests have been carried out in hypersonic, rarefied flow by a direct simulation Monte Carlo code at the altitudes of 65 and 85 km, in the range of angle of attack 0-40 deg. and with flap deflection equal to 0, 15 and 30 deg.. Effects of the flap deflection have been quantified by the variations of the aerodynamic force and of the longitudinal moment. The shock wave-boundary layer interaction and the shock wave-shock wave interaction have been also considered. A possible interaction of the leading edge shock wave and of the shock wave arising from the vertex of the convex corner, produced on the lower surface of the airfoil when the flap is deflected, generates a shock wave whose intensity is stronger than those of the two interacting shock waves. This produces a consistent increment of pressure and heat flux on the lower surface of the flap, where a thermal protection system is required.

• Proceedings of the KSME Conference
• /
• 2000.11b
• /
• pp.568-572
• /
• 2000

A numerical investigation was performed to determine the effect of airfoil thickness on the optimum Gurney flap height using NACA 00XX series airfoils. Seven airfoils which have 3% chord thickness difference were used. These were NACA 0006, 0009, 0012, 0015, 0018, 0021, and 0024. A Navier-Stokes code, FLUENT, 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 fur our computational method, numerical studies for NACA 4412 airfoil were made and compared with already existing experimental data for this airfoil by Wadcock. For every NACA 00XX airfoil, Gurney flap heights ranging from 0.5% to 2.0% chord were changed by 0.5% chord interval and their effects were studied. With the numerical solutions, the relationship between $(L/D)_{max}$ and airfoil thickness as a function of flap height and the relationship between $(L/D)_{max}$ and flap height as a function of airfoil thickness were investigated. The same relationship for $(C_l)_{max}$ also were shown. From these results, the optimum flap size for each airfoil thickness can be determined and vice versa.

• Archives of Reconstructive Microsurgery
• /
• v.14 no.1
• /
• pp.42-49
• /
• 2005

Between June 1989 and may 2004 Ipsilateral vascularized fibular transposition was performed on nine patients with segmental tibial defects combined with infection following trauma. Ipsilateral vascularized fibular graft was performed on two or three stage according to the degree of infection. Initially free vascular pedicled graft was done followed by ipsilateral vascularized fibular graft. Type of free flap used is scapular free flap 3 cases, latissimus dorsi free flap 5 cases and dorsalis pedis flap 1 cases. The patients were followed for an average of 3.4 years. the average time to union was 6.7 months, and in all patients the graft healed in spite of complication. Complication was free flap venous thrombosis in 1 cases, persistent infection in 1 cases, delayed bony union at the distal end of fibular graft in 2 cases. The results showed that more faster bony union was seen in which cases firmly internally fixated and more faster hypertrophy of graft in which cases was permitted to ambulate on early weight bearing and more faster healing in which cases debrided more meticulously. Reconstruction of tibia defect with free flap followed by Ipsilateral fibular transposition is a useful and safe method to avoid the potential risk of infection for patients with tibial large bone defect and soft tissue defect associated with infection.

• Archives of Reconstructive Microsurgery
• /
• v.23 no.2
• /
• pp.101-104
• /
• 2014

Reconstruction of soft tissue defects of the knee has always been a challenging task for plastic surgeons. Various reconstructive choices are available depending on the location, size, and depth of the defect relative to the knee joint. Defects on the knee joint have several characteristic features. The use of a free flap is preferred for reconstructions involving obliteration of large-cavity defects, but recipient pedicle isolation can be difficult because of the extent of the injury zone. Furthermore, the true defect during knee joint flexion is larger than during knee joint extension, and a durable flap is necessary for joint movement. We report for the first time on the use of pedicled perforator flaps for reconstruction of bilateral knee defects in a 76-year-old woman. The operative procedure required skeletonizing the perforators of an antero-lateral thigh flap and antero-medial thigh flap and rotating the flap in the defect. The patient returned to normal daily activity and had a full range of motion two months after the accident. The shorter operating time with decreased donor site morbidity and its durability make this flap a valuable alternative for soft tissue reconstruction of the knee.

• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.1476-1477
• /
• 2008

This paper reports on a flexible flap valve actuated by electromagnetic force under a constant pressure source. The flexible flap valve consists of the three main components: a flexible flap with a steel disk embedded in PDMS, an electromagnetic actuator and two glass plates with inlet and outlet. Sealing lip structures for improving the valve characteristics are added on the outlet of the bottom glass substrate. The flap valve is fabricated by the spin-coating process, the EDM process, SU-8 mold process and oxygen plasma treatment. The dimension of an assembled flap valve is $12mm{\times}20mm{\times}28mm$. The stroke volume of the flap valve is measured for various pressures and open times. When the input voltage of 30 V is applied for 0.33 s, the minimum stroke volume of the flap valve is 70 ${\mu}L$ at 50 kPa.