• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.68-75
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• 2008

화재시뮬레이션용 소프트웨어인 FDS (Fire Dynamics Simulator)의 수직벽 화재 시뮬레이션에 있어서의 문제점을 파악하기 위해, 수직벽 프로필렌 화재에 대한 시뮬레이션을 수행하였다. 성능기반설계 등에 널리 사용되고 있는 이 전산유체역학 모델에 포함되어있는 주요 매개변수의 기본값을 사용한 경우, 수직벽 화재에서는 정확도가 매우 낮음을 확인하였다. 프로필렌 연소율 $10.08g/m^2$-s과 $29.29g/m^2$-s에 대한 주요 매개변수의 조사를 수행한 결과, 스마고린스키 상수(Smagorinsky constant)가 기본값인 0.2에서 수직벽에 형성된 경계층이 층류로 예측되었다. 스마고린스키 상수가 0.1일 때 온도분포가 실험과 비교적 잘 일치하였으나 벽면에서의 열유속에는 큰 오차가 있음을 확인하였다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2005.10a
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• pp.135-140
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• 2005

There are cofferdam and watertight wall to prevent of circulation or pollution during building of ocean structures like a dam and bridge in the harbors area and the sea. Inflow fluid and base of structure is important thing as one of the structural design factors for this interception wall like a cofferdam and watertight wall. In this study, it is revealed that at least 500 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics. The turbulent shear flow around a surface-mounted vertical wall was investigated by using the two-frame PIV(CACTUS 3.1) system and Mean velocity distributions have also been measured in the whole flow field.

• Proceedings of KOSOMES biannual meeting
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• 2005.11a
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• pp.153-158
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• 2005

The turbulent shear flaw around a surface-mounted vertical wall was investigated using the two-frame PIV(CACTUS 3.1) system. From this study, it is revealed that at least 500 instantaneous velocity field data are required for ensemble average to get reliable turbulence statistics, but only 200 field data are sufficient for the time-averaged mean velocity information The flow has an unsteady recirculation region post vertical wall with bottom gap, followed by a slow relaxation to the fiat-plate boundary layer flow. The time-averaged reattachment length estimated from the streamline distribution is about x/H=3H. The large eddy structure in the separated shear layer seems to have signification influence on the development of the separated shear layer and the reattachment process.

• Fire Science and Engineering
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• v.23 no.5
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• pp.133-137
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• 2009

The Fire Dynamics Simulator (FDS), a computational fluid dynamics model for fire simulation, was applied to propylene vertical wall fires, to confirm its accuracy in simulation of vertical wall fires. The temperature profiles at the center of the burner obtained for mass loss rates per unit area in the range of $7.0{\sim}29.29g/m^2-s$ were compared with those of experiment. Comparisons of the heat flux distributions along the vertical centerline on the wall surface were made with the measurements. It was shown that the computed temperature profiles were in good agreement with the experiment. It was also noted that the peak temperature near the wall was underpredicted, the heat flux was too high compared with the measurements, and hence improvements are required for FDS in simulation of the vertical wall fires.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.404-409
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• 2009

수직벽 화재 예측의 정확성을 확인하기 위하여 화재 시뮬레이션용 전산유체역학 모델인 Fire Dynamics Simulator를 프로필렌 수직벽 화재에 적용하였다. 단위면적당 연소율 $7.0{\sim}29.29g/m^2-s$에 대한 버너 중심에서 측정한 온도분포와 비교한 결과, 최고온도가 낮게 예측되는 것 외에는 실험과 잘 일치하였다. 또 연소율의 증가에 따라 경계측의 두께가 일관되게 증가하였다.

• Journal of Korean Society of Steel Construction
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• v.25 no.1
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• pp.93-102
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• 2013

This paper describes the experimental study on the structural behavior of the vertical plane connection between a reinforced concrete wall and a steel plate concrete wall under out-of-plane flexural loads. The specimen was tested under a dynamic test with the use of cyclic loads. As a result of the test, ductile failure mode of vertical bars was shown under a push load and the failure load was more than that of the nominal strength of the specimen. However, the shear failure mode of the connection was confirmed in case of a pull test and thus demonstrates a need for a shear reinforcement.

• Fire Science and Engineering
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• v.22 no.3
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• pp.181-187
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• 2008

Numerical simulation of natural convection along a vertical wall was carried out to evaluate the computational fluid dynamics simulator, which is to be utilized for study of vertical wall fires. The computed velocity and temperature profiles were compared with measurements over the turbulent boundary layer formed along the wall of 4m high and constant temperature. It fumed out that the simulator with default parameters failed to predict the turbulent natural convection showing the boundary layer flow laminar. The grid size $\Delta$x=5mm, ${\Delta}y={\Delta}z=10mm$ and Smagorinsky constant of the large eddy simulation $C_s$=0.1 were chosen through parametric investigations. Though turbulent mixing was not enough, the velocity distribution near wall, peak velocity, and temperature profile in the turbulent boundary layer agreed well with the measurements.

• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.3
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• pp.27-33
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• 2009

A computational study has been performed out to evaluate the effect of a vertical porous barrier on the pressure oscillations in a supersonic cavity. The porous barriers with different perforations were vertically installed into a rectangular cavity at Mach numbers 1.50, 1.83 and 2.50. TVD finite difference MUSCL scheme was employed to solve the two-dimensional, unsteady, compressible Navier-Stokes equations. The present vertical porous barrier considerably altered the characteristics of the time-dependent shear layers that occur at the upstream edge of cavity and remarkably reduced the pressure oscillations inside the supersonic cavity. The present results showed that the effectiveness of passive control using the present porous vertical barrier is dependent on Mach number and the perforation of the porous barrier.

• Fire Science and Engineering
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• v.22 no.3
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• pp.188-193
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• 2008

Numerical simulation was carried out for a propane fire of mass transfer rate 3g/m^2-s$ on a 1m high vertical wall. The objectives of this study are to confirm the outcomes of evaluation of the simulator through simulation of natural convection, and to compare the results of the wall fire with those of previous studies. It was confirmed that the simulated boundary layer was laminar at C_s=0.2$ while it was turbulent at C_s=0.1$. The z direction velocity showed lack of turbulent mixing as seen in the natural convection case, and the profiles of temperature and velocities were in relatively good agreement with those of experiment and previous simulation. It was found that the air entrainment into the boundary layer was well predicted.

• Transactions of the Korean Society of Mechanical Engineers
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• v.5 no.3
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• pp.230-237
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• 1981

임의의 기하학적형태 단면을 가진 수직덕트내 층류조합대류열전달에서 벽온일정인 경계조건에 대하여는 Nayak[12], Giuidice[13]의 유한요소법해가 있다. 본 연구는 경계조건으로 벽에서의 열플러스가 비균일(균일한경우 포함)한 경우를 대상으로 유한요소법에 의한 해석을 시도한 것으로 예시에서 보는 바와 같이 수직해는 벽해밀과 좋은 일치를 보이고 있다.