• 한국항공우주학회지
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• 제32권8호
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• pp.129-137
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• 2004

본 연구에서 시험부 크기 $30mm{\times}35.6mm$, Run Time 20초인 소형-저가의 초음속 풍동을 개발하였다. 개발원 교육용 초음속 풍동은 단속적 불어내기식형이며 , 노즐 블록 교체형으로 설계되었다. 본 연구를 통하여 초음속 풍동에 사용되는 대형-고가의 기계장비를 기존 소형의 상용 제품으로 대체하여 제작 단가를 낮추었다. 그리고 초음속 풍동의 핵심 기술인 노즐 설계를 비롯한 전체적인 초음속 풍동 설계 기술을 확보하였다. 풍동 시험부에서의 초음속 유동장 형성 및 유동 안정성에 대한 성능검증 실험을 수행하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1329-1332
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• 2007

In this study, the design method of flexible wing model for gust response measurement wind tunnel test was presented. The design concept proposed herein was validated by modal testing of the flexible wing model manufactured. In addition, aeroservoelastic modeling method for flexible wing model was presented and validated by comparing the gust response analysis results from the method proposed herein with those of commercial software. The gust response characteristics of the flexible wing model was studied by wind tunnel test for measuring the flexible wing gust response due to the induced gust excitation by gust generator. The aeroservoelastic modeling methods proposed and the wind tunnel test results obtained in this study can be applied for wind tunnel testing of the flexible wing for gust response alleviation.

• 한국항공운항학회지
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• 제13권4호
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• pp.92-99
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• 2005

A closed-circuit type wind tunnel is designed, which has a test section with the dimensions $1.2(W){\times}1.2(H){\times}3.4(L)$. A subsonic wind tunnel is designed to improves educational circumstances and promote ground tests. It is constituted of an exchangeable test section, first and second diffusers, a fan, a settling chamber, a contraction, and 4 corners. The maximum velocity in the test section is 70m/s and the contraction ratio is 6.25:1. Input power in the wind tunnel is about 96.1 kw (128.8 hp) and its energy ratio is 3.89. It has the dimension of about $7.4(W){\times}3.6(H){\times}21.7m(L)$. The wind tunnel designed in this investigation will be an effective educational and investigational equipment.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 춘계학술대회논문집
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• pp.542-547
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• 2004

The objective of this study is 0 estimate wind pressure acting on soundproof tunnel and noise reduction through the tunnel. For the purpose various shape of scale models were prepared and drag forces acting on each models were measured in wind tunnel. And numerical simulation was performed to confirm experimental results. As a result the lowest drag force coefficient of 0.59 was obtained in the case of arch roof shape model. Noise reduction through soundproof tunnel was simulated by using ray tracing method according to various open ratio of its roof area.

• Wind and Structures
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• 제22권4호
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• pp.455-476
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• 2016

In both structural and environmental wind engineering, the vertical variation of wind direction is important as it impacts both the torsional response of the high-rise building and the pedestrian level wind environment. In order to systematically investigate the vertical variation of wind directions (i.e., the so-called 'twist effect') induced by hills with idealized geometries, a series of wind-tunnel tests was conducted. The length-to-width aspect ratios of the hill models were 1/3, 1/2, 1, 2 and 3, and the measurements of both wind speeds and directions were taken on a three-dimensional grid system. From the wind-tunnel tests, it has been found that the direction changes and most prominent at the half height of the hill. On the other hand, the characteristic length of the direction change, has been found to increase when moving from the windward zone into the wake. Based on the wind-tunnel measurements, a descriptive model is proposed to calculate both the horizontal and vertical variations of wind directions. Preliminarily validated against the wind-tunnel measurements, the proposed model has been found to be acceptable to describe the direction changes induced by an idealized hill with an aspect ratio close to 1. For the hills with aspect ratios less than 1, while the description of the vertical variation is still valid, the horizontal description proposed by the model has been found unfit.

• Wind and Structures
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• 제19권6호
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• pp.649-663
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• 2014

The present paper discusses the characteristics of unsteady aerodynamic forces on long-span curved roofs. A forced vibration test is carried out in a wind tunnel to investigate the effects of wind speed, vibration amplitude, reduced frequency of vibration and rise/span ratio of the roof on the unsteady aerodynamic forces. Because the range of parameters tested in the wind tunnel experiment is limited, a CFD simulation is also made for evaluating the characteristics of unsteady aerodynamic forces on the vibrating roof over a wider range of parameters. Special attention is paid to the effect of reduced frequency of vibration. Based on the results of the wind tunnel experiment and CFD simulation, the influence of the unsteady aerodynamic forces on the dynamic response of a full-scale long-span curved roof is investigated on the basis of the spectral analysis.

• Wind and Structures
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• 제5권2_3_4호
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• pp.151-164
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• 2002

Predictions of the pedestrian level wind speeds for the downtown area of Auckland that have been obtained by wind tunnel and computational fluid dynamic (CFD) modelling are presented. The wind tunnel method involves the observation of erosion patterns as the wind speed is progressively increased. The computational solutions are mean flow calculations, which were obtained by using the finite volume code PHOENICS and the $k-{\varepsilon}$ turbulence model. The results for a variety of wind directions are compared, and it is observed that while the patterns are similar there are noticeable differences. A possible explanation for these differences arises because the tunnel prediction technique is sensitivity to gust wind speeds while the CFD method predicts mean wind speeds. It is shown that in many cases the computational model indicates high mean wind speeds near the corner of a building while the erosion patterns are consistent with eddies being shed from the edge of the building and swept downstream.

• Wind and Structures
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• 제16권4호
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• pp.393-409
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• 2013

This paper uses ten years of on-site monitoring data for the Confederation Bridge to derive wind loads and investigate whether the bridge has experienced its design wind force effects since its completion in 1997. The load effects derived using loads from the on-site monitoring data are compared to the load effects derived using loads from the 1994 and 2009 wind tunnel aerodynamic model tests. The research shows, for the first time, that the aerodynamic model-based methodology originally developed in 1994 is a very accurate method for deriving wind loads for structural design. The research also confirms that the bridge has not experienced its specified (i.e., unfactored) wind force effects since it was opened to traffic in 1997, even during the most severe event that has occurred during this period.

• 국제초고층학회논문집
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• 제8권4호
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• pp.283-290
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• 2019

Corner cut, corner chamfered or a building shape change are adopted in the design of tall buildings to achieve aerodynamic superiority as well as response reduction. Kikuchi et.al pointed out that large negative peak external pressures can appear near the inside corner of set-back low rise buildings. It is therefore necessary to pay attention to facade design around steps in building surfaces. Peak wind pressures for corner cut or corner chamfered configurations are given in the AIJ code. However, they cannot be applied where there are many variations of vertical and horizontal steps. There has been no previous systematic research on peak wind pressures around steps in building surfaces. In this study, detailed phenomenon of peak wind pressures around steps in buildings are investigated focusing on vertical and horizontal distances from the building's corner.

• 한국강구조학회 논문집
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• 제24권1호
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• pp.47-58
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• 2012

본 연구에서는 터널 내 통과차량에 의하여 발생하는 풍하중으로 인한 터널라이닝의 동적거동에 대하여 분석하였다. 차량으로 인한 풍하중은 목표지점을 지나가는 차량에 대하여 압력과 팽창을 나타내는 시간함수를 이용하여 모형화 하였으며, 파형강판으로 이루어진 터널라이닝은 3차원 쉘 요소를 사용하였다. 쉘 요소로 모델링된 3차원 터널라이닝의 동적해석은 많은 양의 메모리와 시간이 요구되지만 파형강판의 동적특성을 반영하는 한편 최대한 단순화된 모형을 제시하여 해석에 이용하였다. 터널라이닝의 변위를 분석하기 위해 다양한 차량 주행 조건 및 맞바람 풍속이 고려되었다. 차량과 풍속이 증가하면 응답 또한 증가하였으며, 최대변위는 차량이 120km/h로 교차주행 시 25mm로 나타났다. 연속주행 시 응답에 미치는 영향은 단독주행 응답보다 2.5% 이내로 크지 않게 나타났다. 따라서 숏크리트가 적용되지 않는 독립구조체 터널라이닝의 경우동적거동은 반드시 고려해야하는 것으로 판단된다.