• 환경영향평가
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• 제20권4호
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• pp.575-583
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• 2011

In this study, the plausible grid size was estimated to increase for efficiency of reservoir management using 3 dimensional water quality model. To validate utilization of a real time water quality management tool, ELCOM-CAEDYM model was applied to Soyang reservoir in korea. 100m grid size can represent the real topography and take out exact analysis results. $400{\times}400m$ grid can be easily used to analysis because of data capacity. Consequently, the grid size of 200m or 300m was recommended to establish 3D model considering the required simulation time and the irrelevance between horizontal grid size and vertical distribution for temperature and turbidity analysis.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.386-389
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• 2008

In this paper grid generation of unstructured quadrilateral surface grids is described. The current approach uses conventional Advancing Front Method which is used to generate unstructured triangular grids. Grid cell size control is done by using closeness-based global interpolation method controlled by pre-described control elements. Algorithm and procedure for quadrilateral grid generation using AFM method and cell size control method are described. Examples of quadrilateral grid generation are shown, and difficulties and problems related to the current approach are also discussed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.386-389
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• 2008

In this paper grid generation of unstructured quadrilateral surface grids is described. The current approach uses conventional Advancing Front Method which is used to generate unstructured triangular grids. Grid cell size control is done by using closeness-based global interpolation method controlled by pre-described control elements. Algorithm and procedure for quadrilateral grid generation using AFM method and cell size control method are described. Examples of quadrilateral grid generation are shown, and difficulties and problems related to the current approach are also discussed.

• 지질공학
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• 제25권3호
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• pp.369-376
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• 2015

최근 국내에서 터널 내 지하수 유출량 산정을 위해 MODFLOW와 같은 지하수 수치모델이 많이 이용되고 있다. 수치 모델의 경우 격자망 설계가 터널 유출량 산정 결과에 큰 영향을 주는 것으로 알려져 있으나, 모델 설계 시 명확한 기준없이 연구자에 따라 임의의 크기로 격자망이 설정되어 왔다. 따라서 본 논문에서는 해석해와 수치해를 비교하는 방법을 통하여 격자의 크기가 수치모델의 유출량 산정 오차에 미치는 영향을 분석하였으며, 최적의 격자망 설정 방법을 제시하였다. 해석해와 수치해의 불일치는 부적절한 격자망 설정뿐만 아니라 모델 영역의 경계 효과에 의해서도 발생하는 것으로 나타났다. 따라서 수치모델의 경계 효과 성분을 제거한 후 격자의 크기가 터널 유출량 산정 오차에 미치는 영향을 분석하였으며, 결론적으로 정확한 유출량 산정 결과를 나타내는 터널 크기와 격자 크기의 관계식을 도출하였다. 도출된 관계식은 유한차분 수치모델에서 등가우물격자반경과 격자 크기와의 관계식과 동일한 것으로 나타났다.

• 한국물환경학회지
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• 제28권1호
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• pp.26-37
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• 2012

Multi-dimensional hydrodynamic and water quality models are widely used to simulate the physical and biogeochemical processes in the surface water systems such as reservoirs and estuaries. Most of the models have adopted the Eulerian grid modeling framework, mainly because it can reasonably simulate physical dynamics and chemical species concentrations throughout the entire model domain. Determining the optimum grid cell size is important when using the Eulerian grid-based three-dimensional water quality models because the characteristics of species are assumed uniform in each of the grid cells and chemical species are represented by concentration (mass per volume). The objective of this study was to examine the effect of grid-size of a three dimensional hydrodynamic and water quality model (EFDC) on hydrodynamics and mass transport in the Saemangeum Reservoir. Three grid resolutions, respectively representing coarse (CG), medium (MG), and fine (FG) grid cell sizes, were used for a sensitivity analysis. The simulation results of numerical tracer showed that the grid resolution affects on the flow path, mass transport, and mixing zone of upstream inflow, and results in a bias of temporal and spatial distribution of the tracer. With the CG, in particular, the model overestimates diffusion in the mixing zone, and fails to identify the gradient of concentrations between the inflow and the ambient water.

• 대한방사선기술학회지:방사선기술과학
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• 제43권4호
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• pp.265-272
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• 2020

The purpose of this study was to investigate the dose-volume indices and radiobiological indices according to the change in dose calculation grid size during the planning of nasopharyngeal cancer VMAT treatment. After performing the VMAT treatment plan using the 3.0 mm dose calculation grid size, dose calculation from 1.0 mm to 5.0 mm was performed repeatedly to obtain a dose volume histogram. The dose volume index and radiobiological index were evaluated using the obtained dose volume histogram. The smaller the dose calculation grid size, the smaller the mean dose for CTV and the larger the mean dose for PTV. For OAR of spinal cord, brain stem, lens and parotid gland, the mean dose did not show a significant difference according to the change in dose calculation grid size. The smaller the grid size, the higher the conformity of the dose distribution as the CI of the PTV increases. The CI and HI showed the best results at 3.0 mm. The smaller the dose calculation grid size, the higher the TCP of the PTV. The smaller the dose calculation grid size, the lower the NTCP of lens and parotid. As a result, when performing the nasopharynx cancer VMAT plan, it was found that the dose calculation grid size should be determined in consideration of dose volume index, radiobiological index, and dose calculation time. According to the results of various experiments, it was determined that it is desirable to apply a grid size of 2.0 - 3.0 mm.

• 한국화재소방학회논문지
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• 제26권5호
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• pp.67-72
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• 2012

대규모 건축물의 화재 시뮬레이션에 사용되는 FDS의 적정 격자크기를 제시하기 위해 3개의 개구부가 있는 $20{\times}10{\times}3m^3$ 크기의 실과 $44{\times}48{\times}10m^3$ 크기의 클린룸에 대한 화재 시뮬레이션을 수행하였다. z방향 격자크기를 0.2 m로 고정하고 x, y방향의 격자크기 0.1~1.0 m(종횡비 0.5~5.0)에 대한 온도와 가시거리의 변화를 비교하였다. x, y방향 적정 격자크기는 0.5 m(종횡비 2.5) 이내이며, 1.0 m의 경우에는 오차가 큰 것으로 나타났다. 온도, 가시거리 등의 변동으로 인해 유효피난시간의 산정에 주의가 요구되고, 불가피하게 큰 격자를 사용해야하는 경우에는 격자크기에 대한 검토가 필요하며, 더 큰 격자를 사용하기 위해 격자의 종횡비에 관한 추가연구가 필요함을 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 춘계학술대회논문집
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• pp.867-871
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• 2007

Noise map is very efficient tool to evaluate the road traffic noise. However, calculation time and accuracy of noise map heavily depend on the grid size of noise map. In this study, effects of grid size on the prediction results of road traffic noise map have been investigated in detail for urban and rural areas, respectively, and efficient grid size for the noise map has been proposed.

• 한국소음진동공학회논문집
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• 제20권2호
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• pp.199-204
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• 2010

Noise map is very efficient tool to evaluate the road traffic noise. However, calculation time and accuracy of noise map heavily depend on the grid size of noise map. In this study, effects of grid size on the prediction results of road traffic noise map have been investigated in detail for urban and rural areas, respectively, and efficient grid size for the noise map has been proposed.

• 한국지리정보학회지
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• 제8권3호
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• pp.23-33
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• 2005

GIS를 이용하여 수문지형인자를 추출하는 경우 격자크기가 수문모형에 어떠한 영향을 미치는지를 경사도를 산정함으로써 비교 연구하였다. 격자의 크기를 여러 단계에 걸쳐 분류하여 작업을 진행하였으며, 이를 유역 전체를 하나로 취급한 경우와 각 지류를 나누어 작업을 수행한 경우로 구분하여 비교 분석하였다. 또한 유역 면적의 크기에 따라 격자크기 결정이 미치는 영향을 살펴보기 위하여 대상유역 내의 소유역을 선정하여 동일한 방법으로 격자 크기를 추출하는 작업을 수행하였다. 따라서 본 연구에서는 수문지형인자의 추출에 있어서 GIS를 이용하는 경우 효과적인 격자의 크기 적용에 대한 기준을 확립하는데 도움을 주고자 하는 것에 그 목적을 두고 있다.