• Title, Summary, Keyword: rectangular walls

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Numerical Study of Natural Convection in a Rectangular Enclosure with Cooling Strip (냉각부(冷却部)를 갖는 사각형(四角形) 밀폐공간내(密閉空間內)의 자연대류(自然對流)에 관(關)한 수치해석(數値解析))

  • Lee, Cheong-Ouk;Seo, Jeong-Yun;Kim, Chong-Bo
    • Solar Energy
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    • v.6 no.2
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    • pp.54-61
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    • 1986
  • The influence on natural convection was studied by solving the partial differential equations within a rectangular enclosure which have a cooling strip at the right side wall of the space, a isothermally heated bottom plate and adiabatic two other walls. Computation was carried out for the range of Grashof number from $5*10^3$ to $2.5*10^5$ with Plandtl number of 0.73. The results have been obtained in cases of four aspect ratios and various strip sizes. Temperature and Stream function distributions have been plotted using explicit finite difference method in two dimensional, laminar flow, and also mean Nusselt number and Local Nusselt number have been obtained.

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A Study on Natural Convection Flows Using Particle Image Analysis (입자영상해석에 의한 자연대류 유동에 관한 연구)

  • Bae, D.S.;Kim, N.S.;Cho, W.H.
    • Journal of the Korea Society For Power System Engineering
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    • v.4 no.2
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    • pp.11-16
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    • 2000
  • Simultaneous quantitative measurements are made of the velocity fields for two-dimensional natural convection in a rectangular enclosure using PIV(Particle Image Velocimetry). The experiments are performed at a Prandtl number of 6.62, an aspect ratio of 1.0, Rayleigh numbers from $1.294{\times}10^6\;to\;3.8841{\times}10^6$, and angles of inclination of $0^{\circ},\;30^{\circ}\;and\;60^{\circ}$ inside a $30mm{\times}30mm{\times}8mm$ cavity made of an acrylic glass 10mm, with two isothermal copper walls kept at a prescribed temperature. The experimental results agreed very well with the numerical results. It was found that the flow consisted of a large double convection cell at angle of inclination of $60^{\circ}$.

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An Experimental Study on Melting Process of Ice in a Rectangular Cavity with Different Wall Temperature (양벽온이 다른 장방형용기 내에서 얼음의 융해과정에 관한 실험적 연구)

  • Lim, W.T.;Kim, B.C.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.7 no.4
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    • pp.547-555
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    • 1995
  • Melting process of ice in a rectangular cavity with different temperature walls has been studied experimentally. Front shape of ice and melting rate were affected by initial temperature of ice and variation of temperature distribution and density gradient. When the hot wall temperature was below $8^{\circ}C$, the melting rates were higher at the bottom than those of at the top due to the density inversion, but with increasing the hot wall temperature the melting rates at the top were affected by hot wall and were higher than those of at the bottom. When the initial temperature of ice was low, melting rates were low, but with increasing the time melting rates were almost the same with those of each initial temperature of ice.

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Heat Transfer in an Axisymmetric Cavity of a Rectangular Tube (사각관로의 축대칭 공동부에서의 열전달)

  • Park, Yong-Il
    • Solar Energy
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    • v.10 no.1
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    • pp.31-37
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    • 1990
  • An experimental study for the flow in an axisymmetric cavity of rectangular tube was performed. The pressure and heat transfer coefficient along the side and opposite-walls of the cavity were measured. The cavity length was varied from 80mm to infinity during the experiment. As the result of this study, it was found that as the length of cavity increased beyond the reattachment point, the heat transfer coefficient decreased. It was also found that the mean heat transfer coefficient became maximum near the reattachment point.

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Wind tunnel study of wind loading on rectangular louvered panels

  • Zuo, D.;Letchford, C.W.;Wayne, S.
    • Wind and Structures
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    • v.14 no.5
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    • pp.449-463
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    • 2011
  • Drag forces on a rectangular louvered panel, both as a free-standing structure and as a component in a generic low-rise building model, were obtained in a wind tunnel study. When tested in a building model, the porosity ratio of the wall opposite the louvered panel was varied to investigate its effect on the loading of the louvered panel. Both mean and pseudo-steady drag coefficients were obtained. Comparisons with the provisions for porous walls in contemporary loading standards indicate that for some opposite wall porosity ratios, the standards specify significantly different wind loads (larger and smaller) than obtained from this wind tunnel study.

Experimental compressive behavior of novel composite wall with different width-to-thickness ratios

  • Qin, Ying;Chen, Xin;Zhu, Xing-Yu;Xi, Wang;Chen, Yuan-Ze
    • Steel and Composite Structures
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    • v.36 no.2
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    • pp.187-196
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    • 2020
  • Double skin composite wall system owns several structural merits in terms of high load-carrying capacity, large axial stiffness, and favorable ductility. A recently proposed form of truss connector was used to bond the steel plates to the concrete core to achieve good composite action. The structural behavior of rectangular high walls under compression and T-shaped high walls under eccentric compression has been investigated by the authors. Furthermore, the influences of the truss spacings, the wall width, and the faceplate thickness have been previously studied by the authors on short walls under uniform compression. This paper experimentally investigated the effect of width-to-thickness ratio on the compressive behavior of short walls. Compressive tests were conducted on three short specimens with different width-to-thickness ratios. Based on the test results, it is found that the composite wall shows high compressive resistance and good ductility. The walls fail by local buckling of steel plates and crushing of concrete core. It is also observed that width-to-thickness ratio has great influence on the compressive resistance, initial stiffness, and strain distribution across the section. Finally, the test results are compared with the predictions by modern codes.

Structural Performance of Shearwall with Sectional Shape in Wall-type Apartment Buildings (단면현상에 따른 벽식구조 전단벽의 구조성능 평가)

  • 한상환;오영훈;오창학;이리형
    • Journal of the Korea Concrete Institute
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    • v.12 no.4
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    • pp.3-14
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    • 2000
  • Structural performance of the walls subjected to lateral load reversals depends on various parameters such as loading history, sectional shape, reinforcement, lateral confinement, aspect ratio, axial compression, etc. Thus, the performance of the shearwall for wall-type apartment should be evaluated properly considering above parameters. This study investigates the effect of sectional shape on the structural performance of the wall. Sectional shape of the specimen is rectangular, barbell and T. Based on this experimental results, all specimens behaved as ductile fashion and failed by concrete crushing of the compression zone. Deformation index of those specimens evaluated better than 3 of ductility ratio, and 1.5% of deformability specified by seismic provision. Moreover, the performance of the rectangular shaped specimen, whose compression zone was confined with U-bar and cross tie, was as good as the barbell shaped specimen. Therefore, if we considered construction practice such as workmanship and detailing, shearwall with rectangular section may be more economical lateral load resisting system.

An Experimental Study on Pressure Drop of Boiling Flow within Horizontal Rectangular Channels with Small Heights (미세 수평 사각 유로 내에서의 비등 유동 압력강하에 관한 실험적 연구)

  • Lee, Sang-Yong;Lee, Han-Ju
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.9
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    • pp.1219-1226
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    • 2001
  • Pressure drops were measured for the flow boiling process within horizontal rectangular channels. The gap between the upper and the lower plates of each channel ranges from 0.4 to 2mm while the channel width being fixed to 20mm. Refrigerant 113 was used as the test fluid. The mass flux ranges from 50 to 200kg/㎡s and the channel walls were uniformly heated up to 15kW/㎡. The quality range covers from 0.15 to 0.75. The present experimental conditions coincide with the operating conditions of compact heat exchangers in which the liquid and gas flows are laminar and turbulent. The measured results were well represented by the two-phase frictional multiplier of Lee (2001) which has been developed for air-water two-phase flows within the deviation of $\pm$20%.

Experimental Study of Natural Convection Due to Combined Buoyancy in a Rectangular Enclosure (직각 밀폐용기내의 복합부력에 의한 자연대류에 관한 실험적 연구)

  • 이진호;현명택
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.2
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    • pp.247-256
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    • 1986
  • An experimental investigation was conducted to study natural convection due to temperature and concentration differences between the two opposite end walls of a rectangular enclosure of aspect ratio 0.2. Flow motion in the enclosure appears as a uni-cell flow pattern for the relatively lower concentration and higher temperature differences and vice versa, while it appears as a multicell flow pattern for the comparable temperature and concentration differences. In the multi-cell flow regime, when the cellular flow motiion is very slow, vertical temperature differences within the cells are negligible while the vertical concentration differences are large. In addition, both the temperature and concentration differences are negligible across the interface between the slowly moving cells. For the fast moving cellular flow motion, on thel contrary, vertical temperature differences within the cells are large while the vertical concentration differences are negligible. In this case, temperature differences are negligible and the concentration differences are large across the interface between the fase moving cells.

A Study on Vibration Characteristics in Water Tank with Multi-panels (복수 평판으로 이루어진 접수 탱크 구조물의 진동 특성에 관한 연구)

  • Bae, S.Y.
    • Journal of the Korea Society For Power System Engineering
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    • v.14 no.6
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    • pp.67-74
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    • 2010
  • Many tanks are installed in ship and marine structures. They are often in contact with inner or outer fluid, like ballast, fuel and cargo tanks. Fatigue damages are sometimes observed in these tanks which seem to be caused by resonance with exciting force of engine and propeller. Vibration characteristics of these thin walled tanks in contact with fluid near engine and propeller are strongly affected by added mass of containing fluid. Therefore it is essentially important to estimate the added mass effect to predict vibration of the tanks. Many authors have studied vibration of cylindrical and rectangular tanks containing fluid. Few research on dynamic interaction among tank walls through fluid are reported in the vibration of rectangular tanks recently. In case of rectangular tanks, structural coupling between adjacent panels and effect of vibration modes of multiple panels on added mass have to be considered. In the previous report, A numerical tool of vibration analysis of a 3-dimensional tank is developed by using finite element method for plates and boundary element method for fluid region. In this paper, the coupling effect between panels of a tank on added mass of containing fluid, the effect of structural constraint between panels on each vibration mode for fluid region and mode characteristics in accordance with changing breadth of the plates are investigated numerically and discussed.