• Proceedings of the KSEEG Conference
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• 2007.04a
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• pp.456-458
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• 2007

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2006.04a
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• pp.270-273
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• 2006

예산의 소유역에서 비가 와서 하천수의 유량이 증가 할 때, 하천수 시료를 시계열로 채취하여 하천수를 구성하는 강수, 토양수, 지하수의 상대적인 양을 추적자를 이용한 3성분계 모델을 적용하여 산정하였다. 연구지역에서는 토양수가 전체 유량의 약 5% 내에서 영향을 주었으며 강수와 지하수가 하천수의 대부분을 구성하고 있음이 밝혀졌다.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.5
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• pp.19-30
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• 2016

We presented a hydrodynamic modeling necessary to accurately reproduce shock-induced detonation of pyrotechnic initiator. The methodology for such numerical prediction of shock propagation is quite straight forward if the models are properly implemented and solved in a well-formulated shock physics code. A series of SSGT(Small Scale Gap Test) and detailed hydrodynamic simulation are conducted to quantify the shock sensitivity of an acceptor that contains 97.5% RDX. A TBI(Through Bulkhead Initiator) system, consisting of a train configuration of Donor(HNS+HMX) - Bulkhead(STS) - Acceptor(RDX), were investigated to further validate the interaction between energetic and non-reactive materials for predicting the detonating response for successful operation of such small pyro device.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.37 no.6
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• pp.571-579
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• 2009

For the flow analysis of reactive compressible media involving energetic materials and metallic confinements, a Hydro-SCCM (Shock Compression of Condensed Matter) tool is developed for handling multi-physics shock analysis of energetics and inerts. The highly energetic flows give rise to the strong non-linear shock waves and the high strain rate deformation of compressible boundaries at high pressure and temperature. For handling the large gradients associated with these complex flows in the condensed phase as well as in the reactive gaseous phase, a new Eulerian multi-fluid method is formulated. Mathematical formulation of explosive dynamics involving condensed matter is explained with an emphasis on validating and application of hydro-SCCM to a series of problems of high speed multimaterial dynamics in nature.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.2
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• pp.375-383
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• 2000

A mixed culture isolated from petroleum-contaminated soil was enriched on toluene as a sole carbon and energy source, and degradation characteristics of BTEX(Benzene, Toluene, Ethylbenzene, Xylenes) was observed. In the single-substrate experiments, all the BTEX compounds were degraded, and it was degraded as following orders; toluene, benzene, ethylbenzene, and p-xylene. In the degradation experiments of BTEX mixtures, the degradation rate was decreased compared to that in the single substrate experiment and ethylbenzene was degraded faster than benzene. In the experiments of binary-mixtures, various substrate interactions such as inhibition, stimulation, and non-interaction were observed, and ethylbenzene was shown to be most potent inhibitor of BTEX degradation. In the degradation characteristic studies of xylene isomers, m-xylene and p-xylene were degraded as carbon sources, and it was stimulated in the presence of either benzene or toluene. However, degradation of o-xylene was enhanced only in the presence of benzene.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.2
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• pp.75-85
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• 2016

A pyrotechnic system consisting of donor/acceptor pair separated by a gap relies on shock attenuation characteristics of the gap material and shock sensitivity of the donor and acceptor charges. Despite of its common use, numerical study of such pyrotechnic train configuration is seldom reported because proper modeling of the full process requires precise capturing of the shock wave attenuation in the gap prior to triggering a full detonation of high explosive and accurate description of the high strain rate dynamics of the explosively loaded inert confinements. We apply a Eulerian level-set based multimaterial hydrocode with reactive flow models for pentolite donor and heavily aluminized RDX as acceptor charge. The complex shock interaction, critical gap thickness, acoustic impedance, and go/no-go characteristics of the gap test are quantitatively investigated.

• Journal of Korea Water Resources Association
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• v.31 no.3
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• pp.347-360
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• 1998

Numerical simulations for fluid flow and solute transport in a fracture rock masses are performed by using a transient flow model, which is based on the three-dimensional stochastic and discrete fracture network model (DFN model) and is coupled hydraulic model with mechanical model. In the numerical simulations of the solute transport, we used to the particle following algorithm which is similar to an advective biased random walk. The purpose of this study is to predict the response of the tracer test between two deep bore holes (GPK1 and GPK2) implanted at Soultz sous Foret in France, in the context of the geothermal researches.l The data sets used are obtained from in situcirculating experiments during 1995. As the result of the transport simulation, the mean transit time for the non reactive particles is about 5 days between two bore holes.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.4
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• pp.431-438
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• 2011

Flame lift-off conditions determine the operating conditions of burners. It is known that a flame can be lifted when the Schmidt number (Sc), which is the ratio of the dynamic viscosity to the mass diffusivity, is greater than unity. In this study, the flame lift-off characteristics of non-premixed flames of propane (Sc > 1) and methane (Sc < 1) in a coaxial outer air tube were experimentally compared. The experimental results indicated that stable lifted flames could be obtained even when Sc < 1 in a confined air tube. On the basis of the results of a simple numerical analysis, it was confirmed that a new flame stabilization mechanism exists in the tube. A velocity field is preferentially developed upstream of the flame, and it results in a new stabilization condition. This result can be very useful in explaining the stabilization of the flames of ordinary burners in which a flame is produced in a confined space.