• Structural Engineering and Mechanics
• /
• v.21 no.4
• /
• pp.451-468
• /
• 2005

Effective beam width models are commonly used to obtain the lateral stiffness of flat plate structures. In these models, an effective beam width is defined as the width when the flexural stiffness of the beam element equals the slab stiffness. In this present study, a method to obtain effective beam widths that considers the effects of connection geometry and slab cracking is analytically proposed. The rectangularity of the vertical member for the connection geometry and the combined effects of creep and shrinkage for the slab cracking are considered. The results from the proposed method are compared with experimental results from a test structure having nine slab-column connections.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.25 no.11
• /
• pp.1476-1482
• /
• 2001

Turbulent boundary layer over a flat plate was disturbed by installing an elliptic cylinder with an axis ratio of AR=2. For comparison, the same experiment was carried out for a circular cylinder having the same vertical height. The surface pressure and the heat transfer coefficient on the flat plate were measured with varying the gap distance between the elliptic cylinder and the flat plate. The mean velocity and the turbulent intensity profile of the streamwise velocity component were measured using a hot-wire anemometry. As a result, the flow structure and the local heat transfer rate were modified by the interaction between the cylinder wake and the turbulent boundary layer as a function of the critical gap ratio where the regular vortices start to shed. For the elliptic cylinder, the critical gap ratio is increased and the surface pressure on the flat plate is recovered rapidly at downstream location, compared with the equivalent circular cylinder. The maximum heat transfer rate occurs at the gap ratio of G/B = 0.5, where the flow interaction between the lower shear layer of the cylinder wake and the turbulent boundary layer is strong.

• Journal of Advanced Marine Engineering and Technology
• /
• v.29 no.7
• /
• pp.729-735
• /
• 2005

This paper has dealt with the characteristics of mass and heat transfer of vertical flat plate with free convection. The theory of similarity transformations applied to the momentum and energy equations for free convection. To derive the similarity equation of mass transfer. the equation for conservation of species was added to the continuity. momentum and energy equations. The momentum, energy and species equations set numerically to obtain the velocity, temperature and mass fraction of species as dimensionless. For cases where momentum transport dominates, the thermal boundary layers are shorter than the momentum boundary layer. The relationships between momentum, energy and species were clarified from this study.

• Journal of Energy Engineering
• /
• v.23 no.2
• /
• pp.21-27
• /
• 2014

The influence of the surface roughness on the natural convection heat transfers of a vertical plate were measured experimently. Mass transfer experiments instead of heat transfer experiment were performed based on the analogy. The piecewise electrodes were adopted to measure the local-average Nusselt number. Prandtl number was 2,014 and height of the plate was 0.154m The test results for a smooth surface showed similar heat transfer rate with the Le Fevre heat transfer correlation for a vertical plate. The Nusselt number increased with the roughness Rz $0.5{\sim}14.1{\mu}m$. The test results were presented by a simple correlation.

• Journal of Mechanical Science and Technology
• /
• v.16 no.7
• /
• pp.966-974
• /
• 2002

An analytic approach has been employed to study condensate film thickness distribution inside cave-shaped cavity of a flat plate heat pipe. The results indicate that the condensate film thickness largely depends on mass flow rate and local velocity of condensate. The increasing rate of condensate film for circular region reveals about 50% higher value than that of vertical region. The physical properties of working fluid affect significantly the condensate film thickness, such as the condensate film thickness for the case of FC-40 are 5 times larger than that of water. In comparison with condensation on a vertical wall, the average heat transfer coefficient in the cave-shaped cavity presented 10∼15% lower values due to the fact that the average film thickness formed inside the cave-shaped cavity was larger than that of the vertical wall with an equivalent flow length. A correlation formula which is based on the condensate film analysis for the cave-shaped cavity to predict average heat transfer coefficient is presented. Also, the critical minimum fill charge ratio of working fluid based on condensate film analysis has been predicted, and the minimum fill charge ratios for FC-40 and water are about Ψ$\_$crit/=3∼7%, Ψ$\_$crit/=0.5∼1.3% respectively, in the range of heat flux q"=5∼90kW/㎡.

• Journal of the Korean Society for Advanced Composite Structures
• /
• v.5 no.2
• /
• pp.9-14
• /
• 2014

Main topics in this study is a new structural detail for connection between H-Steel or SRC column and flat plate slab. We carried out to evaluate the punching shear performance of H-steel or SRC column + RC slab system for vertical load and lateral load. From the test results structural characteristics - yield moment, yield rotation, maximum moment, deformation capabilities ect. - are obtained and evaluated. In this paper as a shear reinforcement for supporting region of plate closed stirrup type and shear band are used, and their test results are compared.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.48 no.6
• /
• pp.494-502
• /
• 1999

This paper represents an electrostatic micro plate resonator which consists of a rigid plate suspended with four bridges and a counter electrode. The bridges of the resonator are designed corrugated so that the residual stress are released. The FEM simulation results confirmed that the deflection characteristic of the corrugated bridge is hardly affected by the initial residual tensile stress. One resonator with the corrugated bridges and the other with the flat bridges were fabricated by the boron diffusion process and the anisotropic etch process. The vertical deflection of the fabricated electrostatic resonator was measured with a laser vibrometer, and the data were compared with the calculation results. The deflection of the resonator with the flat bridges is smaller than the deflection of that with the corrugated ones because of the residual stress. The residual stress release effect was confirmed by the fact that the measured deflection of the resonator with the corrugated bridges in close to the calculated deflection of the resonator with the flat ones with the initial stress neglected.

• International Journal of Naval Architecture and Ocean Engineering
• /
• v.6 no.1
• /
• pp.151-161
• /
• 2014

In this study, an experimental investigation has been made of the applicability of outer-layer vertical blades to real ship model. After first devised by Hutchins and Choi (2003), the outer-layer vertical blades demonstrated its effectiveness in reducing total drag of flat plate (Park et al., 2011) with maximum drag reduction of 9.6%. With a view to assessing the effect in the flow around a ship, the arrays of outer-layer vertical blades have been installed onto the side bottom and flat bottom of a 300k KVLCC model. A series of towing tank test has been carried out to investigate resistance (CTM) reduction efficiency and improvement of stern wake distribution with varying geometric parameters of the blades array. The installation of vertical blades led to the CTM reduction of 2.15~2.76% near the service speed. The nominal wake fraction was affected marginally by the blades array and the axial velocity distribution tended to be more uniform by the blades array.

• Proceedings of the KSME Conference
• /
• 2004.04a
• /
• pp.1631-1636
• /
• 2004

The supersonic impinging jet has been extensively applied to rocket launching system, gas jet cutting control, gas turbine blade cooling, etc. In such applications, wall temperature of an object on which supersonic jet impinges is a very important factor to determine the performance and life of the device. However, wall temperature data of supersonic impinging jets are not enough to data. The present study describes an experimental work to measure the wall temperatures of a vertical flat plate on which supersonic, dual, coaxial jet impinges. An Infrared camera is employed to measure the wall temperature distribution on the impinging plate. The pressure ratio of the jet is varied to obtain the supersonic jets in the range of over-expanded to moderately under-expanded conditions at the exit of coaxial nozzle. The distance between the coaxial nozzle and the flat plate was also varied. The coaxial jet flows are visualized using a Shadow optical method. The results show that the wall temperature distribution of the impinging plate is strongly dependent on the jet pressure ratio and the distance between the nozzle and plate.

• Proceedings of the Korea Concrete Institute Conference
• /
• 2003.11a
• /
• pp.659-662
• /
• 2003

Recently, the floor thickness in residence may not be satisfied with the floor vibration criteria although the thickness is evaluated by the serviceability requirements in current design provisions. Thus it is necessary to develop the procedure to determine slab thickness satisfied with the floor vibration criteria. In this study, We proposed the methods to determine the slab thickness satisfied with the vertical floor vibration criteria for several concrete compressive strength of flat plate floor systems. For this purpose Monte Carlo simulation procedure was adopted and both randomness inherent in young modulus of concrete and heel drop intensity were accounted.