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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of computational fluids engineering
Journal Basic Information
Journal DOI :
Korea Society of Computational Fluids Engineering
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Volume & Issues
Volume 6, Issue 4 - Dec 2001
Volume 6, Issue 3 - Sep 2001
Volume 6, Issue 2 - Jun 2001
Volume 6, Issue 1 - Mar 2001
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Simulations of Pollutant Dispersion over Rectangular Building
Hong B. Y. ; Park C. G. ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 1~7
Wind flow perturbations, recirculations and turbulence generated by buildings often dominate air pollutant distributions around buildings. This paper describes dispersion of contaminants in the vicinity of a building by solving the concentration equation based on previously simulated wind flow field. Turbulence closure is achieved by using the standard k-ε two-equation model. The paper shows application of the CIP method for solving a species concentration equation of contaminant gas around a rectangular building for two different sources under conditions of neutral atmospheric stratification. Results have been compared to the experimental data and the previous numerical results by hybrid scheme. The computational results of concentration profiles by the CIP method agree well with experimental data.
Numerical Simulation of Two-Phase Flow for Gas-Solid Particles
Jung H. ; Choi J. W. ; Park C. G. ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 8~14
The phenomena of two-phase suspension flows appear widely in nature and industrial processes. Hence, it is of great importance to understand the mechanism of the gas-solid two-phase flows. In the present study, the numerical simulation has been approached by utilizing the Eulerian-Lagrangian methodology for describing the characteristics of the fluid and particulate phases in a vertical pipe and a 90°square-sectioned bend. The continuous phase(gas phase) is described by the Eulerian formulation and a κ-ε turbulence model is employed to find mean and turbulent properties of the gas phase. The particle properties(velocity and trajectory) are then described by a Lagrangian approach and computed using the mean velocity and turbulent fluctuating velocity of the gas phase. The predictions are compared with measurements by laser-Doppler velocimeter for the validation. As a result, the calculated results show good agreements.
Prediction of the Diffusion Controlled Boundary Layer Transition with an Adaptive Grid
Cho J. R. ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 15~25
Numerical prediction of the diffusion controlled transition in a turbine gas pass is important because it can change the local heat transfer rate over a turbine blade as much as three times. In this study, the gas flow over turbine blade is simplified to the flat plate boundary layer, and an adaptive grid scheme redistributing grid points within the computation domain is proposed with a great emphasis on the construction of the grid control function. The function is sensitized to the second invariant of the mean strain tensor, its spatial gradient, and the interaction of pressure gradient and flow deformation. The transition process is assumed to be described with a κ-ε turbulence model. An elliptic solver is employed to integrate governing equations. Numerical results show that the proposed adaptive grid scheme is very effective in obtaining grid independent numerical solution with a very low grid number. It is expected that present scheme is helpful in predicting actual flow within a turbine to improve computation efficiency.
Direct Numerical Simulation of the Flow Past an Oscillating Circular Cylinder
Kang S. J. ; Tanahashi M. ; Miyauchi T. ; Lee Y. H. ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 26~34
The flow past a circular cylinder forced to vibrate transversely is numerically simulated by solving the two-dimensional Navier-Stokes equations modified by the vibration velocity of a circular cylinder at a Reynolds number of 164. The higher-order finite difference scheme is employed for the spatial discretization along with the second order Adams-Bashforth and the first order backward-Euler time integration. The calculated cylinder vibration frequency is between 0.60 and 1.30 times of the natural vortex-shedding frequency. The calculated oscillation amplitude extends to 25% of the cylinder diameter and in the case of the lock-in region it is 60%. It is made clear that the cylinder oscillation has influence on the wake pattern, the time histories of the drag and lift forces, power spectral density and phase diagrams, etc. It is found that these results include both the periodic (lock-in) and the quasi-periodic (non-lock-in) state. The vortex shedding frequency equals the driving frequency in the lock-in region but is independent in the non-lock-in region. The mean drag and the maximum lift coefficient increase with the increase of the forcing amplitude in the lock-in state. The lock-in boundaries are also established from the present direct numerical simulation.
Prediction of Turbulent Swirling Flow Using A Low-Reynolds-number Reynolds Stress Model
Kim J. H. ; Kim K. Y. ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 35~42
In this study, numerical calculations are carried out in order to evaluate the performance of low-Re Reynolds stress model based on SSG model for a swirling turbulent flow in a pipe. The results are compared with those of k-ε model, GL model and the experimental data. The results show that low-Re Reynolds stress model and GL model give better results than k-ε model. In the region near the wall, low-Re Reynolds stress model improves the predictions. However, there is no large difference between the predictions with two Reynolds stress models.
충격파 불안정성을 제거한 Roe 수치기법
Kim Sung-soo ; Kim Chongam ; Rho Oh-Hyun ; Hong Seung Kyu ;
Journal of computational fluids engineering, volume 6, issue 4, 2001, Pages 43~53