Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of computational fluids engineering
Journal Basic Information
Journal DOI :
Korea Society of Computational Fluids Engineering
Editor in Chief :
Volume & Issues
Volume 4, Issue 3 - Dec 1999
Volume 4, Issue 2 - Sep 1999
Volume 4, Issue 1 - Jun 1999
Selecting the target year
Numerical analysis of flow field around an automobile with variation of yaw angles
Kang D. M. ; Jung Y. R. ; Park W. G. ; Ha S. D. ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 1~11
This paper describes the flow field analysis of an automobile with crosswind effects of 15°, 30° 45° and 60° of yaw angles. The governing equations of the 3-D incompressible Navier-Stokes equations are solved by the iterative time marching scheme. The Chimera grid technique has been applied to efficiently simulate the flow around the side-view mirror. The computated surface pressure coefficients have been compared with experimental results and a good agreement has been achieved. The A- and C-pillar vortex and other flow phenomena around the ground vehicle are evidently shown. The variation of aerodynamic coefficients of drag, lift, side force and moments with respect to yaw angle is systematically studied.
Pollutant Dispersion Analysis Using the Gaussian Puff Model with the Numerical Flowfield Information
Jung Y. R. ; Park W. G. ; Park O. H. ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 12~20
The computations of the flowfield and pollutant dispersion over a flat plate and the Russian hills of various slopes are described. The Gaussian plume and the puff model have been used to calculate concentration of pollutant. The Reynolds-averaged unsteady incompressible Navier-Stokes equation with low Reynolds κ-ε model has been used to calculate the flowfield. The flow data of a flat plate and the Russian hills from Navier-Stokes equation solutions has been used as the input data for the puff model. The computational results of flowfield agree well with experimental results of both a flat plate and Russian hills. The concentration prediction by the Gaussian plume model and the Gaussian puff model also agrees flirty well with experiments.
Numerical Analysis of the flow Characteristics in Intake-Port Piston Head Configurations in a Gasoline Direct-Injection Engine.
Park Chan-Guk ; Park Hyung-Koo ; Lim Myung-Taeck ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 21~27
In this paper, tile characteristics of flow resulting from the configurations of piston head and intake-port of the cylinder in a gasoline-direct-injection engine are investigated numerically. Calculations are carried out from intake process to the end of compression. GTT code which includes the third order upwind Chakravarthy-Osher TVD scheme and κ-ε turbulence model with the law of wall as a boundary condition. As a result, a piston head with a smaller radius of curvature and larger radius gives stronger reverse tumble. It is also shown that as the maximum tumble ratio increases by the configuration of the intake-port the tumble ratio at the end of compression stroke increases. It is concluded that flows at the end of compression stroke can be controlled by the optimum design of intake-port and piston head.
On Numerical Treatment of Pressure Gradient at the Interface Between a Homogeneous Fluid and a Porous Medium
Kim I. S. ; Nam J. H. ; Kim C.-J. ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 28~34
The objective of this study is to present a numerical treatment of the pressure gradient when control volumes are sharing the interface between a homogeneous fluid and a porous medium. Two possible approaches, e.g. linear interpolation and extrapolation, are considered, and they are applied to the case of a steady and two-dimensional curved channel flow which is partially filled with a porous medium. It was found that the linear extrapolation produces a continuous velocity-field at the interface and thus is recommended. On the contrary, the linear interpolation entails a discontinuous velocity field at the interface, thereby warning its use in connection with the Brinkman-Forchheimer-extended Darcy flow model.
Numerical Study on the Shock Wave Focusing of Elliptic Reflectors
Ko C. C. ; Shim E. B. ; Sah J. Y. ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 35~43
In this study, the shock wave focusing of an elliptic reflector is numerically simulated by solving the Euler equations. The numerical method is the second order upwind TVD scheme with a finite volume discretization. For the verification of the present method, we simulate the moving shock wave passing through a two-dimensional corner. The computed isopycnics are compared with the earlier experiment. Numerical results of the elliptic reflectors show that the density and pressure at the focusing point increase linearly as the aspect ratio of the reflector becomes deep. On the other hand, the gas dynamic focal length decreased with the increase of the reflector aspect ratio.
Modification of SST Turbulence Model for Computation of Oscillating Airfoil Flows
Lee Bo-sung ; Lee Sangsan ; Lee Dong Ho ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 44~51
A modified version of SST turbulence model is suggested to simulate unsteady separated flows over oscillating airfoils. The original SST model, which shows good performance in predicting various steady flows, often results in oscillatory behavior of aerodynamic loads in large separated flow regions. It is shown that this oscillatory behavior is due to the adoption of the absolute value of vorticity in generalizing the original model. As a remedy, a modification is made such that the vorticity in the original SST model is replaced by strain rate. The present model is verified for a mild separated airfoil flow at fixed angle of incidence and for unsteady flowfields about oscillating airfoils. The results are compared with BSL model and original SST model. It is illustrated that the present model gives a better agreement with the experimental results than other two models.
A Study of Parallel Implementations of the Chimera Method using Unsteady Euler Equations
Cho K. W. ; Kwon J. H. ; Lee S.S ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 52~62
The development of a parallelized aerodynamic simulation process involving moving bodies is presented. The implementation of this process is demonstrated using a fully systemized Chimera methodology for steady and unsteady problems. This methodology consists of a Chimera hole-cutting, a new cut-paste algorithm for optimal mesh interface generation and a two-step search method for donor cell identification. It is fully automated and requires minimal user input. All procedures of the Chimera technique are parallelized on the Cray T3E using the MPI library. Two and three-dimensional examples are chosen to demonstrate the effectiveness and parallel performance of this procedure.
A DSMC Technique for the Analysis of Chemical Reactions in Hypersonic Rarefied Flows
Chung C. H. ; Yoon S. J. ;
Journal of computational fluids engineering, volume 4, issue 3, 1999, Pages 63~70
A Direct simulation Monte-Carlo (DSMC) code is developed, which employs the Monte-Carlo statistical sampling technique to investigate hypersonic rarefied gas flows accompanying chemical reactions. The DSMC method is a numerical simulation technique for analyzing the Boltzmann equation by modeling a real gas flow using a representative set of molecules. Due to the limitations in computational requirements. the present method is applied to a flow around a simple two-dimensional object in exit velocity of 7.6 km/sec at an altitude of 90 km. For the calculation of chemical reactions an air model with five species (O₂, N₂, O, N, NO) and 19 chemical reactions is employed. The simulated result showed various rarefaction effects in the hypersonic flow with chemical reactions.