• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.12 no.2
• /
• pp.53-69
• /
• 2000

For the case of the capacity increase of Masan-Changwon wastewater treatment plant, the changes of near-field dilution rates due to the increased discharges into Masan Bay from the submerged multipart-diffuser were predicted by using CORMIX model. As the increase of wastewater discharges from currently 280,000 m3f day to 720,000 m3fday by 2011, the dilution rates become much lower than the present rates. To enhance the reduced dilution rates, the engineering design changes of diffuser length and alignment were considered as an optimal engineering option. According to the results of the model simulations for these changes, the dilution rates were increased in the strong ambient current of spring tide, but they were not affected by these changes in the weak current of neap tide in Masan Bay. From the analysis of oceanographic survey data, new outfalls sites have been searched. A promising outfalls site is selected and proposed on the basis of maximum obtainable dilution rates predicted by the model simulations.

• Proceedings of the Earthquake Engineering Society of Korea Conference
• /
• 2000.04a
• /
• pp.249-258
• /
• 2000

본 논문에서는 지반-구조물 상호작용계의 강성에 관련된 물성값들을 지진계측결과를 바탕으로 효과적으로 추정할 수 있는 방법에 대해 연구하였으며 제안된 방법의 검증은 국제공동 연구의 일환으로 최근 대만의 화련에 건설된 대형지진시험구조물에서 계측된 지진 응답을 사용하여 수행하였다. 지반-구조물 상호작용계의 지진응답해석을 위해서 구조물과 근역지반은 축대칭유한요소로 모형화하고 원역지반은 축대칭 무한요소를 사용하였으며 이때 입력 지진하중은 부구조법에 근거한 파입력기법이 고려되었다 지진계측결과를 사용하여 각 영역의 물성값을 제약적 최속강하법을 사용하여 추정하였는데 추정된 계수들을 사용하여 계산된 지진응답이 계측치와 매우 잘 일치하여 추정결과의 타당성을 검증할 수 있었다.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2006.05a
• /
• pp.1954-1958
• /
• 2006

본 연구에서는 관개블럭에서의 유출량을 추정할 수 있는 모형을 개발하였다. 개발된 모형은 관개량 자료, 기후 자료, 강우량 자료, 토양특성 자료 등을 입력받아 관개블럭의 담수심, 증발산량, 심층 침루량, 측방침윤량, 지표배수량 등을 모의하여 유출량을 추정할 수 있도록 구성하였다. 논에서의 물수지방정식을 기본으로 담수심을 추정하고, FAO 수정 Penman식을 이용하여 증발산량을 산정하며, 근역(root zone)의 토양수분을 고려하여 실제증발산량을 산정할 수 있도록 하였다. 심층 침루량(deep percoloation)은 정상상태의 흐름방정식과 Richard식을 이용하여 산정하며, 지표배수량은 광정웨어공식과 Runge Kutta법을 이용하여 추정한다. 관개블럭에서의 최종유출량은 지표배수 관개량, 지표배수량, 침윤손실량의 합으로 계산하도록 모형을 구성하였다.

• KCID journal
• /
• v.9 no.1
• /
• pp.59-69
• /
• 2002

Changes of concentrations and losses of nutrient via infiltration from paddy plot during rice cultivation were monitored. The infiltrated water samples were collected in a ceramic porous cup which was buried at the depth of 30,50,70, and 90cm beneath the

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2000.09a
• /
• pp.126-132
• /
• 2000

하수처리장의 수중확산관에서 방류되는 부력제트는 초기혼합, 중력확장, 이송-확산 등의 과정이 시간적, 공간적으로 규모가 상이한 범위에서 일어나며, 하수방류 해역의 주변수 흐름은 지형특성과 조석의 영향을 받아 3차원적 비정상류 특성을 나타낸다. 이러한 부력제트의 거동을 모의하기 위해서는 일반적으로 근역과 원역을 분할하여 예측하는 방법을 사용하는데, 초기혼합 과정과 중력환장 과정을 예측하기 위해서는 정상상태는 가정한 특성길이 모형이나 제트적분 모형을 사용하고, 원역으로의 이송-확산 과정을 모의하기 위해서는 농도 모형이나 임자추적 모형등을 사용한다. (중략)

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2001.04a
• /
• pp.309-314
• /
• 2001

In this study, the nonlinear soil structure interaction analysis method based on finite element and boundary element method is developed. In the seismic region, the nonlinearity of near field soil has to be considered for more exact reflection of soil-structure interaction effect. Thus, nonlinear finite element program coupled with boundary elements is developed for nonlinear soil-structure interaction analysis. Using the developed numerical algorithm, the nonlinear soil-structure interaction analysis is performed and responses due to dynamic forces and seismic excitation are investigated. The developed method is verified by comparing with previous studies.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2010.05a
• /
• pp.218-222
• /
• 2010

본 연구에서는 ${\sigma}$-좌표계를 기반으로 하는 3차원의 이송확산 모형과 depth-integrated eddy simulation 모형을 결합한 효율적인 3차원 근역 (near-field) 해석모형을 제시하였다. 흐름 모형은 Boussinesq-type equations과 stochastic backscatter model을 기본으로 하고 있다. 이 흐름 모형은 수면의 변화와 바닥으로부터 발생하는 전단력과 파랑의 유동으로부터 발행하는 수심방향의 유속분포를 예측할 수 있다. 이와 같은 흐름 정보를 3차원 ${\sigma}$-좌표계의 이송확산모형에 제공하고 scalar의 이송과 확산에 대한 거동을 계산한다. 기본적인 이송과 이송-확산에 대한 검증 및 개수로에서 정량적 검증과 정성적 검증을 수행하였다. 전반적으로 타당한 결과가 도출되어 모형의 적합성이 있음을 확인하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
• /
• v.7 no.1
• /
• pp.24-32
• /
• 1995

Tsunami generated by the 1992 Nicaragua's west coast earthquake caused 95 persons death, 155 persons injury and 3000 persons homelessness. The previous study done by Imamura et al. (1993) were on the 1992 Nicaragua tsumami generation and propagation which were simulated by using spherical far-field model and Cartesian near-field model, and the computed results with assumption of vertical wall at coast were adjusted by runup ratio to compare with observations. This study using moving boundary model hindcasts El Transito's runup height which was observed as about 6.4-9.9m.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 1999.10a
• /
• pp.243-252
• /
• 1999

Recently several research groups using CORMIX, approved by EPA, have been working on the hydrodynamic mixing processes due to the ocean discharges. It provides a useful tool for analyzing near field mixing characteristics through the outfall system. This paper applies CORMIX 1 & 2 to the Pusan Jungang Effluent Outfall System, which is planned to be in the Gamchun harbour and will be completed in 2011. This model output shows the trajectoral variation of dilution and concentration for three cases of outfall system. Dilution differences have been simulated and found the highest dilution condition under the different displacement of outfall system. On the basis of these outputs it will be proposed the optimum outfall system type and location. This approach might contribute on protecting the serious water quality problem due to the ocean discharge.

• Journal of the Earthquake Engineering Society of Korea
• /
• v.14 no.3
• /
• pp.11-22
• /
• 2010

An analysis method is proposed for the transient linear or nonlinear analysis of dynamic interactions between a flexible dam body and reservoir impounding compressible water under earthquake loadings. The coupled dam-reservoir system consists of three substructures: (1) a dam body with linear or nonlinear behavior; (2) a semi-infinite fluid region with constant depth; and (3) an irregular fluid region between the dam body and far field. The dam body is modeled with linear and/or nonlinear finite elements. The far field is formulated as a displacement-based transmitting boundary in the frequency domain that can radiate energy into infinity. Then the transmitting boundary is transformed for the direct coupling in the time domain. The near field region is modeled as a compressible fluid contained between two substructures. The developed method is verified and applied to various earthquake response analyses of dam-reservoir systems. Also, the method is applied to a nonlinear analysis of a concrete gravity dam. The results show the location and severity of damage demonstrating the applicability to the seismic evaluation of existing and new dams.