• Title/Summary/Keyword: Microscale Turbulence Model

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Electrochemical Ionic Mass Transfer Correlation in Fluid-Saturated Porous Layer

  • Cho, Eun Su
    • Korean Chemical Engineering Research
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    • v.53 no.6
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    • pp.814-817
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    • 2015
  • A new ionic mass transfer correlation is derived for the fluid-saturated, horizontal porous layer. Darcy-Forchheimer model is used to explain characteristics of fluid motion. Based on the microscales of turbulence a backbone mass transfer relation is derived as a function of the Darcy-Rayleigh number, $Ra_D$ and the porous medium Schmidt number, $Sc_p$. For the Darcy's limit of $Sc_p{\gg}Ra_D$, the Sherwood number, Sh is a function of $Ra_D$ only. However, for the region of high $Ra_D$, Sh can be related with $Ra_DSc_p$. Based on the present backbone equation and the electrochemical mass transfer experiments which are electro plating or electroless plating, the new ionic mass transfer correlation is suggested in the porous media.

Validation of Numerical Model for the Wind Flow over Real Terrain (실지형을 지나는 대기유동에 대한 수치모델의 검증)

  • Kim, Hyeon-Gu;Lee, Jeong-Muk;No, Yu-Jeong
    • Journal of Korean Society for Atmospheric Environment
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    • v.14 no.3
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    • pp.219-228
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    • 1998
  • In the present investigation, a numerical model developed for the prediction of the wind flow over complex terrain is validated by comparing with the field experiments. For the solution of the Reynolds - Averaged Clavier- stokes equations which are the governing equations of the microscale atmospheric flow, the model is constructed based on the finite-volume formulation and the SIMPLEC pressure-correction algorithm for the hydrodynamic computation. The boundary- fitted coordinate system is employed for the detailed depiction of topography. The boundary conditions and the modified turbulence constants suitable for an atmospheric boundary- layer are applied together with the k- s turbulence model. The full- scale experiments of Cooper's Ridge, Kettles Hill and Askervein Hill are chosen as the validation cases . Comparisons of the mean flow field between the field measurements and the predicted results show good agreement. In the simulation of the wind flow over Askervein Hill , the numerical model predicts the three dimensional flow separation in the downslope of the hill including the blockage effect due to neighboring hills . Such a flow behavior has not been simulated by the theoretical predictions. Therefore, the present model may offer the most accurate prediction of flow behavior in the leeside of the hill among the existing theoretical and numerical predictions.

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A Numerical Study on the Characteristics of High Resolution Wind Resource in Mountainous Areas Using Computational Fluid Dynamic Analysis (전산유동해석을 통한 산악 지역의 고해상도 풍력자원 특성에 관한 수치연구)

  • Lee, Soon-Hwan
    • Journal of the Korean earth science society
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    • v.32 no.1
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    • pp.46-56
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    • 2011
  • The purpose of this paper is to evaluate the wind energy resources with high spatial resolution in Sunghak and Guduck mountains in Busan Metropolitan area under the various atmospheric stabilities. The numerical model used in this research is A2C (Atmosphere to CFD), mainly applied to assess the regional scale and microscale meteorological phenformin. Wind under the strong atmospheric stability moves around mountain side smoothly due to the strong potential energy. On the other hand, the cavity region on the lee side of mountain tends to be created and expanded as the atmospheric stability decrease. Annually the average distribution of wind power density, turbulence kinetic energy, and vertical wind shear help to explain quantitatively that wind resource near the northern side of Guduck mountain top is more suitable to establish wind energy complex than that in any other regions in the target area.