Pressure distribution on rectangular buildings with changes in aspect ratio and wind direction

Lee, Young Tae,Boo, Soo Ii,Lim, Hee Chang,Misutani, Kunio Techno-Press 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 $k-{\varepsilon}$ model) were solved, and the results were compared with the wind tunnel measurement data. Regarding the turbulence model, the results of the $k-{\varepsilon}$ 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 $k-{\varepsilon}$ 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.

상악 전치부 결손이 발음에 미치는 영향에 관한 연구

노창섭,최대균,우이형,최부병,Roh Chang-Sup,Choi Dae-Gyun,Woo Yi-Hyung,Choi Boo-Byung 대한치과보철학회 1992 대한치과보철학회지 Vol.30 No.3

This study was performed to investigate the phonetic alterations with upper anterior teeth were missing. To compare the changes of the phonations, before and after insertion of the temporary prosthesis, six subjects who lost their upper anterior teeth were selected (2-male, 4-female). Tested sounds (/ga(가), na(나), da(다), ra(라), sa(사), ja(자), cha(차), ta(타), pa(파), ha(하), gi(기), ni(니), di(디), ri(리), si(시), jl(지), chi(치), ti(티), pi(피), hi(히), seu(스), se(세), so(소), su(수)/were programmed into an IBM AT with and without temporary prosthesis. These experiments were analyzed by formants, consonants durations, and energy level changes with an LSI speech work station program. During the pronunciation of the tested sounds (with and without temporary prosthesis), mandibular movements were recorded to a Mandibular Kinesiogram and analyzed . The findings led to the following conclusions: 1. Objective differences could not be found. However, in every informant, subjective improvement could be noticed. 2. There were no persistant correlations of the formant's changes. And in every informant, phonetic changes were variable. 3. There were various changes of the consonant durations in every informant. By and large, those of /si(시), jl(지), chi(치), Pi(피), hi(히)/ were longer than other tested sounds. After insertion of the prosthesis, durations were shorter. Consonants with /i(ㅣ)/ were longer than with /a(ㅏ)/, with or without prosthesis. 4. With and without temporary prosthesis, mandibular movements were various in the frontal view. Mandibular movements showed lateral deviations, and mandibular positions with /si(시), ji(지), ti(티), seu(스), hi(히)/ were nearer to the mandibular rest position. 5. The kinds of temporary prosthesis and conditions of the missing teeth influenced every informant variously, so there were no correlation between informants. 6. Energy levels increased in all tested sounds with a fixed temporary prosthesis. And, there were no differences between before and after insertion of a removable temporary prosthesis. However, sibilant sounds, and consonants with /i(ㅣ)/ showed a little increased energy level.

선성방광염을 동반한 골반지방종증 1례

최창훈,심주명,부명섭,최호철,민권식,최성협 大韓泌尿器科學會 1997 Korean Journal of Urology Vol.38 No.7

2차원 전기저항률 측정에서 전극배열법의 비교

부창진,김호찬,강민제 제주대학교 공과대학 첨단기술연구소 2005 尖端技術硏究所論文集 Vol.16 No.1

Electrical resistance tomograpy(ERT) maps resistivity values of the soil subspace and characterizes buried objects. The characterization includes location, size, and resistivity of buried objects. In this paper, we have made numerical experiments to compare the performance of the Wenner, Schlumberger, pole-pole, and dipole-dipole electrode arrays for two-dimensional resistivity measurement in ERT. In general, the SNR(signal to noise ratio) of resistivity measurement is directly to the measurement voltage level. The pole-pole and Wenner arrays can give the highest signal level. Results of numerical experiments in ERT solved by four electrode array types are presented and compared using Gauss-Newton inversion algorithm.

Wenner 배열을 사용한 대지저항률과 접지저항 분석

부창진,김호찬,이관우 제주대학교 공과대학 첨단기술연구소 2006 尖端技術硏究所論文集 Vol.17 No.2

The grounding system of the subsurface should ensure the safe and reliable operation of power systems, and guarantee a human being's safety in the situation of grounding fault in the power system. The optimal design of grounding systems for subsurface can ensure the equalization of the potential distribution of the ground surface above the grounding system, and can obviously improve the safety of the grounding system. This paper deals with the 2-dimensional reconstruction of the earth's resistivity distribution based on DC resistivity data. This task represents a nonlinear and ill-posed minimization problem with many degrees of freedom. In this work, techniques for regularization and controlling of this problem are depicted and classified. The system of equations as resulting from the application of the Gauss -Newton minimization can be solved efficiently.

웨너-슐렘버거법을 이용한 대지의 다층구조 분석

부창진,김호찬,이관우 제주대학교 공과대학 첨단기술연구소 2006 尖端技術硏究所論文集 Vol.17 No.1

The accurate measurement of soil resistivity and grounding system resistance is fundamental to electrical safety. However, geological and meterological factors can have a considerable effect on the accuracy of conventional measurements and the validity of the measurement methods. This paper presents optimization method of dc resistivity data acquisition system using Wenner and Schlumbeger method.

ERT를 이용한 지하물체의 비파괴 영상화

부창진,김호찬,김문찬,이윤준 제주대학교 공과대학 첨단기술연구소 2004 尖端技術硏究所論文集 Vol.15 No.2

Electrical resistance tomograpy (ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size, and resistivity of buried objects. In this paper, simultaneous iterative reconstruction technieque (SIRT) and truncated least squares (TLS) approach are presented for the solution of the ERT image reconstruction. Results of numerical experiments in ERT solved by the SIRT and TLS approach are presented and compared to that obtained by the Gauss-Newton method.

디스크 드라이브의 주기적 외란 고속 보상 제어

부찬혁,강창익,김호찬 제주대학교 공과대학 첨단기술연구소 2003 尖端技術硏究所論文集 Vol.14 No.2

The control objective in hard disk drives is to move head as fast as possible to target track and position the head over the center of target track in the presence of external disturbances. The external shock or disk clamping error in manufacturing process causes the disk center to deviate from the disk rotation center. The disk shift acts on control system as disturbance and degrades severely the performance of disk drives. In this paper. we present a new controller that compensates for the periodic disturbance very fast. 'The disturbance compensator is arranged in parallel with the state feedback controller. To avoid the interference with the state feedback controller. the compensator creates compensation signal without feedhack of system output until steady state. Finally, in order to demonstrate the superior performance of the proposed compensator. we present some simulation results using a matlab.

濟州道 새마을 운동과 行政의 役割에 關한 硏究 : 1974년도 문교부 학술연구 조성비에 의한 연구 논문

趙文富,韓昌榮 제주대학교 1974 논문집 Vol.6 No.-

1) The outline of the merits of Sae-Maul Movement in Jeju-Province in 1974. ① There are several problems to be discussed hereafter in urban Sae-Maul Movement, list Urban Sae-Maul Movement was fixed and gave the urbanites life and spirit in this year. ② Rural Sae-Maul Movement was mainly developed in North Jeju Country and South Jeju Country. The percentage of mostly undertakings of Rural Sae-Maul movement was above 100% except for 83% merits of the roof betterment undertaking in South Sae-Maul Movement. The achievement cases were characterized by income increasement, circulation development, encouragement of need for achievement and the activities of women. The average farmhouse income of 150 villages in Jeju Province (76% of 196 villages except for 5 villages in Jeju City) is beyond 530,000 won, the average farmhouse income of the whole country. The merit percentage of North Country was 127% and that of South Jeju County was 117% so that in all, the merit percentage of Urban Sae-Maul Movement was 122% ③ The organic cooperation between Jeju Collage Ae-Hyang Dan (homeland development corps composed of the students of Jeju Collage) and the administrative organizations accomplished good results in Sae-Maul Movement. ④ The administrative organization should observe the great interest in Sae-Maul Movement of the islanders dwelling in Japan. Jeju Development Symposium held in October this year under the auspice of Jeju Province was a good example of the organic cooperation between the islanders dwelling in Japan and the administrative organization. To sum up, Sae-Maul Movement in Jeju Province in 1974 was, in the one hand, expanded to the mainland and Japan,not to mention of Jeju Province, and in the other hand, accomplished good results in income incrasement by cultivating the spirit of diligence and self-helf in herited by the islander's forefathers. Also it was noticed that the organic cooperation between colleges and the administrative organizations gave a great impetus to the formation of theory of Sae-Maul Movement as well as to framing a scheme in solving related problems. 2) The role of public abminisaton contributing for Sae-Maul Movemont in Jeju-province. ① The regional development and the role of public administration. The regional development means the synthetic development including social and cultural de-velopment as well as economic development. The latter half of the 20th century, the state must fulfil its function as an inducer, and specially in our country, a developing country, Sae-Maul Movement as regional development had to be induced by public administration. But the new community movement have to be a voluntary movemevt aud a movement of supporting oneself. ② The conditions fo regional develodment by the Sae-Maul Movement in Jeju-province. Before Sae-Maul Movement, althhough we could find the regional development as the expansion of a basic establishment in Jeju-province, we could not find it as increasing the income of the inhabitants. After Sae-Maul Movement, in 1973 we can find out the yield of 137 times as compared with it of 1960 in the production of a mandarin orange, and the income of 1599 times as compared with it of 1960 in tourism income. ③ The role of public administration for Sae-Maul Movement in Jeju-province and its direction from now onward. We can find out the positive role and the negative role in the role of pubeic administration for Sae-Maul Movement in Jeju-province. The positive role iucludes the inducemeut of the motivation and the active support, and the negative role includes the negative support and un-coorpeperation. In case of un-coorperation, it means the case that does not aid financial support, and it as soon needs spiritual and technical support in the stage of the developmeut of supporting oneself. The direction of public administration from now onward will have to be aid for the achievement of mental revo lutiou and technical revolution.

이중면 불연속 구형 도파관의 특성 해석

강부식,장재성,이청민 濟州大學校工科大學附屬産業技術硏究所 1993 尖端技術硏究所論文集 Vol.4 No.-

Double-plane steps discontinuity in rectangular waveguide is investigated with ?? mode analysis. This method accounts for the influence of evanescent fields and power transmission due to higher order modes. For these discontinuites the electromagnetic fields are derived and the scattering matrix is derived by applying the continuous condition in discontinuity. The scattering coefficients of a X-band to Ku-band waveguide transition as well as of resonant iris with finite thickness(t=2.0㎜) are calculated and compared with Patzelt's result. The scattering coefficients of the resonant iris(a=7.112㎜, b=3.556㎜, a₁=4.0㎜, b₁=1.0㎜, t=0.5㎜) are calculated and compared with Bornemann's results.