• Title/Summary/Keyword: wind bell

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Aeroelastic analysis of bridges using FEM and moving grids

  • Selvam, R. Panneer;Govindaswamy, S.;Bosch, Harold
    • Wind and Structures
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    • v.5 no.2_3_4
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    • pp.257-266
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    • 2002
  • In the recent years flow around bridges are investigated using computer modeling. Selvam (1998), Selvam and Bosch (1999), Frandsen and McRobie (1999) used finite element procedures. Larsen and Walther (1997) used discrete vorticity procedure. The aeroelastic instability is a major criterion to be checked for long span bridges. If the wind speed experienced by a bridge is greater than the critical wind speed for flutter, then the bridge fails due to aeroelastic instability. Larsen and Walther (1997) computed the critical velocity for flutter using discrete vortex method similar to wind tunnel procedures. In this work, the critical velocity for flutter will be calculated directly (free oscillation procedure) similar to the approaches reported by Selvam et al. (1998). It is expected that the computational time required to compute the critical velocity using this approach may be much shorter than the traditional approach. The computed critical flutter velocity of 69 m/s is in reasonable comparison with wind tunnel measurement. The no flutter and flutter conditions are illustrated using the bridge response in time.

Adaptive p-finite element method for wind engineering

  • Selvam, R. Panneer;Qu, Zu-Qing
    • Wind and Structures
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    • v.5 no.2_3_4
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    • pp.301-316
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    • 2002
  • An important goal of computational wind engineering is to impact the design process with simulations of flow around buildings and bridges. One challenging aspect of this goal is to solve the Navier-Stokes (NS) equations accurately. For the unsteady computations, an adaptive finite element technique may reduce the computer time and storage. The preliminary application of a p-version as well as an h-version adaptive technique to computational wind engineering has been reported in previous paper. The details on the implementation of p-adaptive technique will be discussed in this paper. In this technique, two posteriori error estimations, which are based on the velocity and vorticity, are first presented. Then, the polynomial order of the interpolation function is increased continuously element by element until the estimated error is less than the accepted. The second through sixth orders of hierarchical functions are used as the interpolation polynomials. Unequal order interpolations are used for velocity and pressure. Using the flow around a circular cylinder with Reynolds number of 1000 the two error estimators are compared. The result show that the estimated error based on the velocity is lower than that based on the vorticity.

Chemical Composition and Lead Isotope Ratio of Poong-Tag(Wind Bell) from Winggyeong Site, Cyeongju (경주 왕경지구 금동풍탁(金銅風鐸)의 성분조성과 납동위원소비)

  • Chung, Young-Dong;Kang, Hyung-Tae;Huh, Il-Kwon;Cho, Nam-Chul
    • Journal of Conservation Science
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    • v.19
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    • pp.67-72
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    • 2006
  • The chemical compositions and lead isotope ratio of Poong-Tag(wind bell) bell excavated from Wanggyeong site, Gyeongju have analyzed by ICP and TIMS. The analysis result of chemical composition of Poong-Tag shows that it consists of 92:4 ratio of Cu:Sn. Other 8 minor elements(Pb, Zn, Fe, Ag, Ni, As, Sb and Co) show the concentration of below 0.2% respectively. This result means that Poong-Tag have made using highly purified Cu and Sn ore. For the study of provenance of raw material with the lead isotope ratio, the origin of the raw material of Poong-Tag can not be presumed owing to beyond the scope. The observation result of microstructure of Poong-Tag show the dendrite structure made through casting process. The chemical composition, microstructure, and lead isotope ratio of Poong-Tag excavated from Wanggyeong site, Gyeongju can be used as fundamental data to compare with other Poong-Tag of different regions and periods.

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Wind Tunnel Test of Smart Un-manned Aerial Vehicle(SUAV) for TR-E2 Configuration (스마트 무인기 TR-E2 형상 풍동시험 결과)

  • Yoon, Sung-Jun;Cho, Ta-Hwan;Chung, Jin-Deog
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.1 s.232
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    • pp.35-45
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    • 2005
  • TR-E2 configuration designed by Bell Textron was tested in KARI 1-m wind tunnel. To explore aerodynamic characteristics for the given configuration, a $12\%$ scaled model was fabricated and tested. Wind tunnel test for TR-E2 had been performed by changing the incidence angles of wing and deflection angles of control surfaces. Test result showed that the lower wing incidence angle has more favorable lift to drag ratio compared with original design. Longitudinal and directional characteristics of TR-E2 were found to be stable for the pitch and yaw motions. However, the lateral stability of TR-E2 is not stable for certain control surface deflection.

A Study on the Ornamental Metal Used in the Roof of Ancient Architecture in Korea (고대 건축의 지붕부에 사용된 금속장식에 관한 연구)

  • Youn, Lily
    • Journal of the Architectural Institute of Korea Planning & Design
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    • v.36 no.2
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    • pp.63-70
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    • 2020
  • In the ancient Buddhist temple area, various metal artifacts are still excavated. Therefore, the aim of this study is to approach the characteristics of ancient architecture through ancient metal artifacts. First, metal decoration of ancient architecture appears for the purpose of structure, decoration, arson. Then, as the method of wood structure is developed, the application is separated into structural, functional and decorative purposes. In ancient times, metal decoration has reduced the role of structure, but its decorative role has expanded. Second, various metallic ornaments were used on the roof of ancient architecture. As the wooden technology developed, the metal decoration was gradually omitted while applying the curve to the roof. Third, the metal ornaments used on the roof of ancient architectures include the ridge central decoration, roof top decoration, a nine-ring decoration, gable board Ornamental Metal, corner flower decoration, eaves nail, wind bell. And subsequent research requires a terminology that can link the results of archeology and Buddhist art through excavation as a result of architecture.

Wind Flow over Hilly Terrain (언덕지형을 지나는 유동에 관한 연구)

  • 임희창;김현구;이정묵;경남호
    • Journal of Korean Society for Atmospheric Environment
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    • v.12 no.4
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    • pp.459-472
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    • 1996
  • An experimental investigation on the wind flow over smooth bell-shaped two-dimensional hills with hill slopes (the ratio of height to half width) of 0.3 and 0.5 is performed in an atmospheric boundary-layer wind tunnel. Two categories of the models are used in the present investigation; six two-dimensional single-hills, and four continuous double-hills. The measurements of the flow field and surface static-pressure distribution are carried out over the Reynolds number (based on the hill height) of 1.9 $\times 10^4, 3.3 \times 10^4, and 5.6 \times 10^4$. The velocity profiles and turbulence characteristics are measured by the pitot-tube and X-type hot-wire anemometer, respectively. The undisturbed boundary-layer profile on the bottom surface of the wind tunnel is reasonably consistent with the power-law profile with $\alpha = 7.0 (1/\alpha$ is the power-law exponent) and shows good spanwise uniformities. The profiles of turbulent intensity are found to be consistent along the centerline of the wind tunnel. The measured non-dimensional speed-up profiles at the hill crest show good agreements with the predictions of Jackson and Hunt's linear theory. The flow separation occurs in the hill slope of 0.5, and the oil-ink dot method is used to find the reattachment points in the leeside of the hill. The measured reattachment points are compared with the numerical predictions. Comparisons of the mean velocity profiles and surface pressure distributions between the numerical predictions and the experimental results show good agreements.

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The Clinical Observation of Digital Infrared Thermographic Imaging on Bell`s palsy (DITI 진단을 통한 Bell`s palsy의 임상적 고찰)

  • Park, Kyung-hwa;Kim, Jong-han;Hwang, Choong-yeon
    • The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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    • v.11 no.1
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    • pp.23-39
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    • 1998
  • The clinical data and thermographic imaging were analyzed on the 100 cases of Bell's palsy who were treated in the Kwang-Ju Oriental Medical Hospita! of Wonkwang University from February to October 1997. All the cases were taken Digital Infrared Thermograph Imaging(DITI) before treatment and 30 cases of them were taken follow up imaging again after recovery. And the following results were obtained. 1. Of 100 cases, under teenager occupied $1\%,\;teenager\;8\%,\;2nd\;decade\;14\%,\;3rd\;decade\;11\%,\;4th\;decade\;16\%,\;5th\;decade\;26\%,\;6th\;decade\;16\%,\;7th\;decade\;7\%\;and\;over\;80\;occupied\;1\%$. 2. Male occupied $48\%$ and female occupied $52\%$. 3. $42\%\;of\;male\;and\;23\%$ of female had the affected side at left side. And right facial nerve palsy occured at $29\%\;of\;male\;and\;29\%$ of female. 4. The most common cause of Bell's palsy was cold wind $18\%$, and the next were excessive labor $15\%,\;stress\;12\%,drinking\;2\%\;and\;cold\;food\;1\%$. 5. Thermal pattern were present as hyperthermal pattern in $44\%$ and hypothermal pattern in $22\%$. 6. The DITI showed hyperthermal pattern as close as to the onset day and changes to hypothermal pattern as times passed. 7. The DITI pattern and post-auricular pain, the most common prodomal syndrome, showed no significant relationship. 8. The relationship between the grade of paralysis and thermal patttern of DITI showed no significance. 9. Mean temperature of loci in affected side indicrtted $30.27^{\circ}C\;at\;Yang\;baek,\;30.02^{\circ}C\;at\;Taeyang,\;29.25^{\circ}C\;at\;Geoyo,\;29.62^{\circ}C\;at\;Jichang,\;29.78^{\circ}C\;at\;Hakwan,\;29.61^{\circ}C\;at\;Hyupgeo,\;and\;30.59^{\circ}C$at Yeopoong. 10. Mean temperature of loci in unaffected side showed $30.16^{\circ}C\;at\;Yang\;baek,\;30.02^{\circ}C\;at\;Taeyang,\;29.61^{\circ}C\;at\;Geoyo,\;29.68^{\circ}C\;at\;Jichang,\;29.70^{\circ}C\;at\;Hakwan,\;29.57^{\circ}C\;at\;Hyupgeo,\;and\;29.89^{\circ}C$at Yeopoong. 11. Of 30 cases who were taken follow up imaging again after recovery, the relationship between delta T at loci and symptoms showed no significance. It should be needed further investigation in order to apply them for clinical evaluation.

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Performance and Flow Characteristics of Axial Fan (축류팬의 성능 평가 및 주변 유동 특성)

  • 김재원;정윤영
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.11
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    • pp.972-981
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    • 2000
  • Comprehensive work is done for flows by an axial fan by experimental research. The present model fan is used for air handling device for out-door unit of an air conditioner in home appliance. PIV(Particle Image Velocimetry) system and wind tunnel are adopted for measurements of flows and performance evaluation, respectively. Major experimental conditions are the installation depth of a fan into a bellmouth of it. Optimal position of a fan in an inlet guide tube is observed by examination of fan-performance and flows in both upstream and downstream of the fan. Consequently, in the case of the fan inserted in half depth into the inlet tube, the efficiency of fan shows its maximum value and flow patterns is also streamlined.

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Clinical Study of Two Cases of Facial Diplegia with Continued Facial Palsy (편측 안면마비가 잇따라 발병한 양측 안면마비 환자 2례에 대한 임상적 고찰)

  • Yang, Gi-Young;Lee, Byung-Ryul;Kim, Young-Il
    • Journal of Acupuncture Research
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    • v.25 no.5
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    • pp.205-211
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    • 2008
  • Objectives : This study is designed in order to evaluate oriental medical treatment of facial diplegia with continued facial palsy. Methods : The authors observed patients by Yanagihara's unweighted grading system for operated acupuncture treatment, herbal medicine treatment and physiotherapy. Results & Conclusions : 1. Both facial grade had different scores in Yanagihara's unweighted grading system for 2 cases when the facial palsy occured. 2. Both cases were diagnosed in wind-cold(feng-han) type. 3. The left and right side of face took different amount of time to recover. 4. Facial diplegia was significantly improved.

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The Development and Originality of Wind Chimes of the Goryeo Dynasty (고려시대 풍탁(風鐸)의 전개와 독창성)

  • Lee, Young-sun
    • Korean Journal of Heritage: History & Science
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    • v.52 no.2
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    • pp.292-307
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    • 2019
  • Buddhists have always tended to adorn and embellish Buddhist statues and their surrounding spaces in order to exhibit the grandeur and sublime nature of the Buddha. The various kinds of splendid instruments and implements used in such ornamentation are collectively called jangeomgu in Korean. Thus, the term jangeomgu encompasses articles used to decorate Buddhist statues, halos, and baldachin, as well as Buddhist banners and wind chimes, which are generally hung outside a building. Wind chimes are still widely used at Buddhist temples. In China, judging from various structures such as the Wooden Stupa of Yongningsi in Luoyang and the Dunhuang Caves, wind chimes began to be used around the sixth century. As for Korea, Buddhism was first introduced from China during the Three Kingdoms Period, and Koreans accordingly began to build Buddhist temples and buildings. It would appear that wind chimes came to be used around the time that the first temples were built. The oldest extant wind chime in Korea is the gilt-bronze wind chime of Baekje, discovered at the Mireuksa Temple Site in Iksan. In general, Korean wind chimes dating from the Three Kingdoms Period are classified into two general types according to their shape and elevation, i.e., those shaped like a Buddhist bell and those shaped like a trapezoid. As these two forms of wind chimes have influenced each other over time, those made during the Goryeo dynasty, having inherited the style, structure, and design of the preceding period, display such features. At the same time, the artisans who produced wind chimes pursued technical development and adopted free, yet not extravagant, designs. In particular, Goryeo wind chimes are characterized by original designs created through exchanges with other Buddhist art forms of the same period, such as the embossed lotus design band of Goryeo bells; the bullmun design, which served to display the grandeur of the royal family; the samhwanmun design, which consisted of decorating the interior of a Goryeo incense burner with three holes; Sanskrit designs; and designs inspired by the windows and doors of stone pagodas. In this way, the production of Goryeo wind chimes developed with a focus on purpose while being free of formal constraints. This study started out from the fact that the largest number of Korean wind chimes were produced during the Goryeo dynasty. Therefore, research on wind chimes should be based on those of the Goryeo dynasty, especially since fewer relevant studies have been conducted compared to studies on other forms of Buddhist art. For the purposes of this study, the reasons for the production of wind chimes will be examined first, followed by an examination of the various styles of Korean wind chimes. Then, based on the findings of this investigation, the development and characteristics of the wind chimes produced during the Goryeo dynasty will be explored for each period.