• Journal of the Ergonomics Society of Korea
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• v.26 no.2
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• pp.89-102
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• 2007

Generally, it is well known that driving in tunnel imposes large burden to driver because of spatial constraint, limited visual field and so on. And such a burden of driver result in high accident occurrence. In this reason, studies dealing with features of driving and traffic flow in tunnel have been performed. However, information about characteristics of drivers and traffic in a very long tunnel is not accumulated yet. The purpose of this study is to identify the relations between tunnel length and burden of driver, driving patterns, traffic flow characteristics using the tunnel simulator that realizing various tunnel situations. For this, the tunnel simulation program was developed along 11km-length section. And biological data of 10 subjects gained from driving condition in simulation program was analyzed and compared with the result of real driving condition.

• Geotechnical Engineering
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• v.10 no.2
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• pp.41-56
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• 1994

Under the groundwater level, the tunnel face is affected by the seepage force and the groundwater flow may cause a trouble to the tunnel support systems. The appropriate methods of analysis and design in the tunnel face and the lining, considering groundwater flow according to tunnel drainage condition are presented in this thesis. First, the effect of seepage on the stability of tunnel face was studied. Seepage force was estimated by the 3-D finite element analysis and the stability of tunnel face was checked by analytical method. Furthermore, using the finite difference method the stress and displacement on the face were computed for either case, where the seepage force is or is not considered, and the effect of seepage on the tunnel face stability was evaluated. Second, the effect of seepage force on the tunnel lining when construction is finished and steady state seepage flow occurs was studied and a design methodology considering seepage effect was made. Consequently, in case where the groundwater level remains almost unchanged and the steady state groundwater flow occurs, the proper countermeasures for face staility are required according to the condition of groundwater flow. Moreover, the tunnel lining should be designed and constructed considering the seepage force occuring by the groundwater flow toward the tunnel linings.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.11
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• pp.3695-3705
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• 1996

We designed the hot wind tunnel to reproduce the conditions of utility boiler and carried out its performance test, in order to investigate the particulate two-phase flow behaviour, the fouling and heat transfer characteristics to the heat exchanger. The hot wind tunnel introduces the control system to control the temperature in the test section. The particle is injected into the hot gas stream. The fouling probe (cylindrical tube) is positioned normal to the particulate gas-particle two-phase flow and cooled by the air. The temperature of gas and cooling air, and temperature in the fouling probe are measured as a function of time, giving the local and averaged heat transfer and fouling factor. The shape of particulate deposition adhered to the fouling probe is also observed.

• Proceedings of the KSR Conference
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• 2005.11a
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• pp.448-453
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• 2005

Tunnel excavation is an inevitable process for railroad construction in Korea and it being a one of the major issues of its environmental impact assessment. Ground water flow by tunnel excavation is an important parameter to determine environmental effects. The current method to determine the ground water flow is used a unit number induced a highway construction site. But it does not consider any site characteristics; ground water level, soil properties and others. The purpose of this study is to suggest the determination way of ground water flow considering site characteristics in tunnel construction.

• International Journal of Aeronautical and Space Sciences
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• v.18 no.3
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• pp.425-435
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• 2017

In this work, an overview of flow diagnosis in a shock tunnel is made by means of using established techniques that are easy to setup, economical to arrange, and simple to measure. One flow condition was considered having Mach number of 6 at the nozzle-exit, regarded as freestream. Measured aerothermodynamic data such as shock wave speed, wall static and total pressures, surface heat flux, and shock stand-off distance ahead of test model showed good agreement with calculation. This study shows an overall procedure of flow diagnosis in a shock tunnel in a single manuscript. Outcomes are thought to be useful in the field of education and also in a preliminary stage of high-speed vehicle design and tests, that need to be performed within a short time with decent accuracy.

• Journal of Advanced Marine Engineering and Technology
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• v.32 no.6
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• pp.886-892
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• 2008

The development of fluid mechanics is briefly reviewed and the importance of fluid flows to heat and mass transfer in nature as well as to science and engineering is outlined. This paper presents the experimental results of air flow in the rectangular tunnel which has four different exhaust outlets, each distance of which from the inlet is 0, 30, 60 and 90mm respectively. This experiment is conducted by using the olive oil as the tracer particles and the kinematic viscosity of the air flow is $1.51{\times}10^{-5}\;m^2$/s. The flow is tested at the flow rate of 1.3 $m^3$/h and the velocity of 0.3 m/s. PIV technology can be used to make a good description of the smoke flow characteristics in the tunnel.

• Journal of Advanced Marine Engineering and Technology
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• v.19 no.4
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• pp.27-33
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• 1995

The turbulent flow and heat transfer in the tunnel laminar flow type clean room is investigated by a numerical simulation. The model clean room is assumed to be a rectngular $5m\times3m$, in which a worktable of 0.75m hight, and 1.5m or 3m long at the floor. Major parameters are the inlet flow velocity, inlet hole size and worktable surface distance. The mean Nusselt number is increased by increasing Reynolds number and can be expressed by the correlation equation.

• Journal of computational fluids engineering
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• v.14 no.3
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• pp.115-122
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• 2009

Numerical methods are applied to simulate the smoke behavior in a ventilated tunnel using large eddy simulation (LES) which is incorporated in FDS (Fire Dynamics Simulator) with proper combustion and radiation model. In this study, present numerical results are compared with data obtained from experiments on pool fires in a ventilated tunnel. The model tunnel is $182m(L){\times}5.4m(W){\times}2.4m(H)$. Two fire scenarios with different ventilation rates are considered with two different fire strengths. The present results are analyzed with those from LES without combustion and radiation model and from RANS ($\kappa-\epsilon$) model as well. Temperature distributions caused by fire in tunnel are compared with each other. It is found that thermal stratification and smoke back-layer can be predicted by FDS and the temperature predictions by FDS show better results than LES without combustion and radiation model. The FDS solver, however, failed to predict correct flow pattern when the high ventilation rate is considered in tunnel because of the defects in the tunnel-inlet turbulence and the near-wall turbulence.

• Fire Science and Engineering
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• v.25 no.4
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• pp.94-102
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• 2011

Hot smoke test is done in a subway tunnel. Alcohol trays of 1.0 MW and smoke generators are used for generating hot smoke. The fans equipped with the tunnel are successively run 9 min after smoke generation. It is verified how hot smoke is controlled by fans. Velocity and direction of flow, temperature and smoke density are measured and analyzed for smoke control performance of the tunnel with fans and analyzed from the fire-safety-point of view. Velocity of smoke flow is obtained by using measured velocity and temperature at the ceiling of the tunnel. The time when smoke-control flow is builded up is different for the different positions. Velocity distributions at various positions will be used for the boundaries and the comparison data in numerical simulations for evaluation on smoke-control facilities of subway tunnel.

• Journal of Korean Society on Water Environment
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• v.30 no.5
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• pp.477-485
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• 2014

Imha Reservoir is connected to Andong Reservoir via a diversion tunnel allowing water to pass between. The diversion tunnel is equipped with screens to exclude exotic largemouth bass due to their predatory impacts on prey assemblages resulting in a degradation of species richness of local fish fauna and extinction of local fish populations in Korea. Flow pattern changes resulting from the fish screens and trash racks were investigated using a computational fluid dynamics (CFD) model. Numerical simulations showed that the decrease in the discharge capacity of the tunnel is approximately 8.6% and the headloss coefficient for fish screen at Andong intake tower was determined to be 1.5. In order not to allow the small fishes enough to pass through the wire openings enter into Imha Reservoir through tunnel, the velocity in the tunnel should be greater than 1.48 m/s which is a critical ascending velocity of the bass. This study suggests that it can keep the velocity higher enough to exclude largemouth bass when a gate opens with the condition of 1.0m difference in water stage between two reservoirs.