• International Journal of Aerospace System Engineering
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• 제10권1호
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• pp.1-13
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• 2023

The present study was attempted to investigate flow interference effects and the aerodynamic characteristics of the front and rear wings of a joined-wing aircraft by changing the configuration variables. The study was performed using a computational fluid dynamics(CFD) tool to demonstrate forward flight and analyze aerodynamic characteristics. A total of 9 configurations were analyzed with variations on the position, height, dihedral angle, incidence angle, twist angle, sweepback angle, and wing area ratio of the front and rear wings while the fuselage was fixed. The quantities of aerodynamic coefficients were confirmed in accordance with joined-wing configurations. The closer the front and rear wings were located, the greater the flow interference effects tended. Interestingly, the rear wing did not any configuration change, the lift coefficient of the rear wing was decreased when adjusted to increase the incidence angle of the front wing. The phenomenon was appeared due to an effective angle of attack alteration of the rear wing resulting from the flow interference by the front wing configurations.

• 한국기계가공학회지
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• 제18권12호
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• pp.22-27
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• 2019

In this study, the flow rate and air resistance pressure were analyzed on models a, b, and c due to the front wing angle of the airplanes. Models a, b, and c have front wing angles of 120°, 100°, and 160°, respectively. The results of the flow analyses showed that the flow rate and air resistance pressure of model c were observed to be higher than models a and b. The airplane model with a larger angle to the front wing is thought to be the best model for flight. This result can be applied to development of the best in-flight airplane.

• 한국의상디자인학회지
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• 제15권2호
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• pp.15-26
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• 2013

The purpose of this study is to offer basic data for designing and making of brassiere with the consideration of the physiological nature of man. Each of 3/4-cup wired upward-support-type Mold Bra of 75 size with basic pad made at three representative domestic companies (A, B and C Company) was selected for analysis of pattern and components. The following is the result of this study. 1. That Company A's bra had the highest cup, relatively narrow width, the widest front-center and the highest front center at front pad. That of Company B had relatively short wing over the base and much difference at the height of cup depending on the presence of wire. That of Company C had low and wide cup, the widest bust span and the front center width, the front center height of front pad, the base length of front pad and the length of wings were observed to be of the figures between those of Company A and B. 2. The Bra of Company A had the biggest front center angle of $6^{\circ}$, while that of Company C had the biggest wing angle of $18^{\circ}$. The Bra of Company B showed the biggest difference of patterns depending on the presence of wire. Those of Company A and C showed very similar shape when wire was inserted. 3. The order of making brassiere is following: making of exterior mold cup${\rightarrow}$ sewing exterior cup and circumference of mold${\rightarrow}$ sewing base and wings${\rightarrow}$ sewing binding tape to base${\rightarrow}$ sewing cup and main pad${\rightarrow}$ sewing binding tape to upper sides and upper part of wings${\rightarrow}$ sewing wire-tape to interior base of cup${\rightarrow}$ inserting of wire inside wire-tape${\rightarrow}$ sewing hook & eye on the back of wings${\rightarrow}$ sewing shoulder string.

• 한국지반공학회논문집
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• 제32권1호
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• pp.5-18
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• 2016

본 연구에서는 모형실험을 통해 균질모래지반에 매설된 횡력을 받는 무리말뚝의 수평저항력을 산정하는데 가장 큰 영향을 주는 배면토의 저항형태를 파악하였다. 저항거동 형태는 회전절점, 쐐기 파괴각, 쐐기 날개각으로 파악하였다. 실험은 지반의 상대밀도, 말뚝의 폭, 말뚝의 간격과 배열을 달리하여 수행하였다. 그 결과 직렬말뚝에서의 지반거동 양상은 전열과 중간열이 같았고 후열의 경우 전열과 중간열 보다 작은 값을 나타내었다. 병렬말뚝의 경우 지반거동 양상이 단독말뚝과 같게 나타났다. 실험 결과를 바탕으로 회전절점, 쐐기 파괴각, 쐐기 날개각 산정 값 들을 식으로 제안하였다.

• 한국항공우주학회지
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• 제30권3호
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• pp.1-7
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• 2002

LEX를 가진 델타형 날개 모델을 사용한 풍동실험을 통하여 LEX가 델타형 날개 윗면의 표면압력분포에 미치는 영향에 대한 연구를 수행하였다. 풍동실험의 유속은 40m/sec, 전압과 전온도는 각각 101Pa, 278K이었으며, 단위길이당 레이놀즈 수는 $1.76{\times}10^6$이었다. LEX는 날개의 표면압력분포를 매우 많이 변화시키었다. LEX가 없는 경우에 비하여 표면압력의 피크치가 시위 앞부분에서는 감소하였으나 뒷부분으로 갈수록 그리고 받음각이 증가할수록 피크치도 증가하였다. 스팬방향 압력구배도 시위 앞부분에서는 완만하였으나 뒤로 갈수록 증가하였다. 또한 LEX가 있는 경우에는 모든 위치에서 받음각의 증가에 따라 표면압력 피크치도 거의 선형적으로 증가하였다.

• 복식문화연구
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• 제16권3호
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• pp.502-517
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• 2008

The purpose of the study lies in the measurements of breast shapes and upper body types for the women in their 40's, with the use of 3D measurement system, and in the presentation of brassiere patterns fit for their body types. As for the study method, 3D human body types were analyzed with RapidForm 2006, and the upper-body types and breast shapes were statistically classified through technical statistics analysis, cluster analysis, t-test, variance analysis, and cross analysis. The wearing tests went through the comparison of the brassieres of three makers in the market and the experiment brassieres(first and second) and then the evaluations were made by the subjects, the outer appearance assessment by experts, and 3D measurements. The findings of the study indicated that the evaluation of experiment brassieres was excellent in every item, and he significant difference was found out particularly in the items of pressure, rear center, front center, breast underneath, adequate level by wing, and adequate level by armhole. According to the results of 3D evaluation, experiment brassieres had a highest point in fitness with no physical pressure at the wing part and no overall deviation at the cup art. The pattern comparison showed the differences in the parts of total cup angle, cup circumference length, lower cup height, wing length, and wing angle.

• 항공우주시스템공학회지
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• 제16권6호
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• pp.54-63
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• 2022

최근 다양한 형태의 전기추진 항공기가 개발 중이다. 전기추진 항공기에 장착되는 프로펠러의 위치는 항공기 공력성능에 큰 영향을 미칠 수 있다. 날개 앞에 장착된 프로펠러는 프로펠러 주변과 하류방향으로 복잡한 선회 유동(Swirl Flow)을 발생시킨다. 선회 유동으로 발생하는 올려흐름과 내리흐름은 날개의 유효받음각에 영향을 미친다. 날개의 길이 분포 방향으로 발생하는 유효받음각 분포변화는 날개의 공력 하중분포에 영향을 준다. 본 연구에서는 날개에 장착된 프로펠러의 위치가 변화하면서 발생하는 프로펠러-날개 상호작용이 날개의 공력 하중분포에 미치는 영향을 연구했다. 프로펠러-날개 상호작용이 날개에 미치는 영향을 해석하기 위해, 프로펠러에 의한 선회 유동을 Actuator Disk Theory를 사용하여 나타냈다. VSPAERO를 사용하여 날개에서 발생하는 공력을 계산했다. 본 연구방법을 사용하여 얻은 계산결과는 프로펠러-날개 모델을 사용한 풍동시험 자료와 비교·검증했다. 연구결과 프로펠러와 날개 사이의 거리가 날개의 공력특성에 미치는 영향은 크게 나타났다. 축방향 및 날개길이 방향의 거리 증가는 양항비를 증가시켰다. 프로펠러가 날개 상단에 위치할 경우 더 큰 양항비를 얻을 수 있었다.

• 한국항공우주학회지
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• 제48권2호
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• pp.109-117
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• 2020

기존 정렬 격자의 많은 제약 조건들을 완화할 수 있는 patched-grid 알고리즘을 이용하여 효율적으로 정렬 격자계를 구성하였다. EFD-CFD 워크숍의 case 4: 삼각 날개-원통형 동체 형상에 크게 3가지의 접근 방식을 적용하여 기존의 격자 생성 문제점들을 해결하였고, 실험값과 비교하여 검증하였다. 고 받음각 영역에서 표면 압력 분포가 실험값과 다소 차이를 보였다. 마하수의 증가에 따른 피칭 모멘트의 기울기 변화를 분석하였고 이는 tuck under 현상으로 설명할 수 있었다. 초음속 영역에서는 형상 앞에 궁형 충격파가 발생함으로써 삼각익 뒷전까지 양력을 발생시키는 영역이 확장되었다. 또한, 마하수와 받음각에 따라 압력 중심과 무게 중심의 위치를 비교하여 피칭 모멘트의 경향성을 분석하였다.

• Wind and Structures
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• 제4권3호
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• pp.227-246
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• 2001

The objective of this study is to understand the flow above the front edge of low-rise building roofs. The greatest suction on the building is known to occur at this location as a result of the formation of conical vortices in the separated flow zone. It is expected that the relationship between this suction and upstream flow conditions can be better understood through the analysis of the vortex flow mechanism. Experimental measurements were used, along with predictions from numerical simulations of delta wing vortex flows, to develop a model of the pressure field within and beneath the conical vortex. The model accounts for the change in vortex suction with wind angle, and includes a parameter indicating the strength of the vortex. The model can be applied to both mean and time dependent surface pressures, and is validated in a companion paper.

• 건축역사연구
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• 제31권6호
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• pp.59-68
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• 2022

This paper is an architectural historical study on Chimi of Hwangnyongsa Temple. In this research, the shape and cross-section of the chimi are reviewed. The results of the study are as follows. The chimi is a form in which the head part facing the maru is omitted, and the upper and lower body are separated. The upper and lower bonds are assembled into a two types of joint throughout the side of the torso, and then bound with an iron strap. Because of the absence of ridge line in the front, and the narrow curved surface which makes the side plate close to the plane, the entire cross-section is triangular, and the rear plate maintains the shape of the chimi. The naerimmaru connected to the side of the chimi has a slope, so it is clear that the chimi was used on the woojingak-jibung(hipped-roof), and the wing part and back of the chimi are erected on the side roof. The height of the yongmaru and chunyeomaru is about the same and the roofing tiles of those are in contact. The roofing tiles of chunyemaru should be cut to fit the angle of the contacting part. The maru is 30 stories high of roofing tiles as a result of the on-board survey. Based on reference on the shape and timing of the production of chimi, the height of chimi, and the maru is believed to have been built before the Unified Silla Period and used in buildings with at least seven-kan frontage. Buildings corresponding to these construction conditions can be seen as Central hall and East hall in Hwangnyongsa temple.