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난류경계층 내 놓인 사각물체 주위의 높이와 방위각에 따른 압력변동특성연구
부수일,임희창 한국풍공학회 2017 한국풍공학회지 Vol.21 No.1
The purpose of this study is to investigate the flow characteristics around a building with square cross section placed in a thick turbulent boundary layer with the changing different heights and oblique angle. Wind tunnel experiment was performed to understand the flow and load characteristics around the body. Three different Reynolds numbers (i.e. 10.4×104 (H1), 29.4×104 (H2), 43.2×104 (H3)) were based on the height of each body and wind speed U. The azimuth angles varied in the range of 0 – 90°. As a result, it was observed that the surface pressure characteristics on the bodies highly depended upon the height of the structures. In addition, the azimuth angles of the on-coming flow also highly affected the separation characteristics occurring at the edge around the rectangular structures. 본 연구는 두꺼운 난류경계층 내에 놓인 구조물의 높이와 방위각이 달라짐에 따라서 나타나는 구조물 주위의 유동특성을 파악하고자 하였다. 구조물 주위의 유동특성을 파악하기 위해 대기경계층 풍동실험을 수행하었다. 구조물의 높이는 3가지로 변화시켰으며, 방위각은 0∼90°까지 변화시켰다. 풍동실험의 레이놀즈수는 각 구조물 높이에 따라 다르게 나타나며 각각의 레이놀즈수는10.4×104(H1), 29.4×104(H2), 43.2×104(H3) 이다. 연구결과로서 높이와 방위각이 변화함에 따라 모서리에서 발생하는 박리현상이 변화하고 이는 구조물의 표면압력과 섭동압력에 상당한 영향을 끼치는 것을 확인할 수 있었다.
세대에 따른 스마트폰 사용 실태 차이에 대한 탐색 연구
김예종,부수안,허인순,허균 한국수산해양교육학회 2017 水産海洋敎育硏究 Vol.29 No.6
The purpose of this research is to investigate the difference in the usage of smartphone according to generation. Based on the previous research, the difference was analyzed as independent variable, usefulness and ease as a dependent variable. For this purpose, 80 adults and 20 teenagers living in Korea were randomly sampled and 100 surveys carry out using the SPSS 22.0 program. The results of the research are as follows. First, it is analyzed that there is a difference in usefulness according to the use of smartphone in daily life by generation. Second, it is analyzed that there is a difference in easiness of using smartphone in daily life by generation. Third, the most favored factor is the function of the new product and the lowest consideration factor is the price when purchasing smartphones. Fifth, it is analyzed that there is a difference in purpose of using smartphone in daily life by generation. Especially, SNS and information search were the most common in all generations, and learning and smart banking were the least.
Pressure distribution on rectangular buildings with changes in aspect ratio and wind direction
이영태,부수일,임희창,Kunio Misutani 한국풍공학회 2016 Wind and Structures, An International Journal (WAS Vol.23 No.5
This study aims to enhance the understanding of the surface pressure distribution around rectangular bodies, by considering aspects such as the suction pressure at the leading edge on the top and side faces when the body aspect ratio and wind direction are changed. We carried out wind tunnel measurements and numerical simulations of flow around a series of rectangular bodies (a cube and two rectangular bodies) that were placed in a deep turbulent boundary layer. Based on a modern numerical platform, the Navier–Stokes equations with the typical two-equation model (i.e., the standard k-e model) were solved, and the results were compared with the wind tunnel measurement data. Regarding the turbulence model, the results of the k-e model are in overall agreement with the experimental results, including the existing data. However, because of the blockage effects in the computational domain, the pressure recovery region is underpredicted compared to the experimental data. In addition, the k-e model sometimes will fail to capture the exact flow features. The primary emphasis in this study is on the flow characteristics around rectangular bodies with various aspect ratios and approaching wind directions. The aspect ratio and wind direction influence the type of wake that is generated and ultimately the structural loading and pressure, and in particular, the structural excitation. The results show that the surface pressure variation is highly dependent upon the approaching wind direction, especially on the top and side faces of the cube. In addition, the transverse width has a substantial effect on the variations in surface pressure around the bodies, while the longitudinal length has less influence compared to the transverse width.