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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of computational fluids engineering
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Journal DOI :
Korea Society of Computational Fluids Engineering
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Volume & Issues
Volume 9, Issue 4 - Dec 2004
Volume 9, Issue 3 - Sep 2004
Volume 9, Issue 2 - Jun 2004
Volume 9, Issue 1 - Mar 2004
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Study on a post-processing program for flow analysis based on the object-oriented programming concept
Na J. S. ; Kim K. Y. ; Kim B. S. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 1~10
In the present study, a post-processing program is developed for 3D data visualization and analysis. Because the graphical user interface(GUI) of the program is based on Qt-library while all the graphic rendering is performed with OpenGL library, the program runs on not only MS Windows but also UNU and Linux systems without modifying source code. The structure of the program is designed according to the object-oriented programming(OOP) concept so that it has extensibility, reusability, and easiness compared to those by procedural programming. The program is organized as modules by classes, and these classes are made to function through inheritance and cooperation which is an important and valuable concept of object-oriented programming. The major functions realized so far which include mesh plot, contour plot, vector plot, streamline plot, and boundary plot are demonstrated and the relevant algorithms are described.
Prediction of Vortex Reducing Effect by a Peforated Baffle in the Inlet Plenum of a Research Reactor
Park J. H. ; Chae H. T. ; Park C. ; Kim H. I. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 11~17
CFD analysis was performed to figure out flow behavior in the inlet plenum of new research reactor where coolant is injected to the flow tubes with the fuel assembly. The computation results showed that large-scale vortices are generated in the inlet plenum by flow stream injected from inlet pipe. These vortices are divided into small vortices and reversed their revolution. They may lead to flow-induced vibration of fuel assembly, moreover, which has been regarded as a cause of fretting wear of fuel assembly. Also there is an another important thing that average velocity of each flow-tube is uneven showing difference in maximum 18%. So it has been suggested that perforated baffle will be installed to prevent the formation of vortex in the inlet plenum. Two perforated baffles, one is flow skirt and the other is muffler type flow straightener, were proposed and their effect was evaluated using commercial CFD code, Fluent. According to CFD analysis for two perforated baffles, it was confirmed that both of them can prevent or reduce vortex formation in the inlet plenum and make average velocity of each flow tube more even.
Prediction of Flow Behavior and Pressure Drop of Spirally Corrugated Steel Pipe
Park Jong-Hark ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 18~22
Numerical investigation has been conducted to figure out flow behavior and pressure drop characteristics of spirally corrugated steel pipe which is widely used in civil, industrial and agricultural field owing to many advantages such as good corrosion resistance and durability, strength, easy and quick installation. Also the poly-ethylene coating spirally corrugated steel pipe has the long life under condition of sea water immerged. In the present study, flow behavior in the spirally corrugated pipe and influence of P/d/sub h/(ratio of wave pitch to hydraulic diameter) to pressure drop are investigated by CFD with various Reynolds number. And also friction factor is estimated by pressure drop obtained by flow analysis. According to computation results, the flow runs spirally up and down along the spiral corrugation in the vicinity of wall, but the effect of spiral corrugation disappears in core region of pipe. As P/d/sub h/ becomes small, more pressure drop occurs in spirally corrugated Pipe. Besides, friction factor augmentation becomes much larger as Re increases. In case of p/d/sub h/=0.38, Pressure drop and friction factor of spirally corrugated pipe are about four times larger than smooth pipe at Re: 1.46×10/sup 6/.
Hybrid RANS/LES Simulation of Subsonic Cavity Flow
Chang K. S. ; Park S. O. ; Choi S. K. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 23~29
A numerical simulation of an incompressible cavity flow is conducted using the hybrid turbulence model. The model adopted is a modified type of DES using k- ε two-equation model. Cavity geometry and flow condition are based on Cattafesta's experiment. Computational results are compared with the results of Cattafesta's experiment. The simulation successfully predicts the oscillatory features and the Strouhal number of the oscillation compares very favorably with that of the dominant mode of experimental data. Vorticity contours obtained from the simulation data are consistent with the smoke visualization of the Cattafesta's experiment. The coherent structures of cavity flow are also investigated using Q criterion.
Numerical Study on k-
Turbulence Models for Supersonic Impinging Jet Flow Field
Kim E. ; Park S. H. ; Kwon J. H. ; Kim S. I. ; Park S. O. ; Lee K. S. ; Hong S. G. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 30~35
A numerical study of underexpanded jet and impingement on a wall mounted at various distances from the nozzle exit is presented. The 3-dimensional Wavier-Stokes equations and κ-ω turbulence equations are solved. The grids are constructed as overlapped grid systems to examine the distance effect. The DADI method is applied to obtain steady-state solutions. To avoid numerical instability such as the carbuncle phenomena that sometimes accompany approximate Riemann solver, the HLLE+ scheme is employed for the inviscid flux at the cell interfaces. A goal of this work is to apply a number of two-equation turbulence models based on the w equation to the impinging jet problem.
Numerical Analysis of Low-Speed Flows in Micro-Channels
Chung C. H. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 36~42
Low-speed gas flows in micro-channels are investigated using a kinetic theory analysis. The Boltzmann equation simplified by a collision model is solved by means of a finite difference approximation with the discrete ordinate method. Calculations are made for flows in simple micro-channels and a micro-fluidic system consisting of two micro-channels in series. The results are compared well with those from the DSMC method and an analytical solutions to the Wavier-Stokes equations. It is shown that the present method is a useful tool for the modeling of low-speed flows in micro-channels.
Investigation on Numerical Integration for Radiation Heat Transfer in Radiating Fluid
Han Cho Young ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 43~51
Interaction between fluid flow and thermal radiation has received considerable attention due to its numerous applications in engineering field. In this case the thermofluid properties of radiating fluid vary with the variation of temperature field caused by absorption and emission of radiant heat. To analyze the radiation heat transfer in radiating fluid, the simultaneous solution of the radiative transfer equation (RTE) and the fluid dynamics equations is required. This means that the numerical procedure used for the RTE must be computationally efficient to permit its inclusion in the other submodels, and must be compatible with the other transport equations. The finite volume method (FVM) and the discrete ordinates method (DOM) are usually employed to simulate radiation problems in generalized coordinates. These two representative methods are examined and compared, especially in view of the numerical integration of the radiation intensity over solid angle. The FVM shows better accuracy than the DOM owing to less constraints of the selection of control angle.
Development of a 3-D Unsteady Viscous Flow Solver on Deforming Unstructured Meshes
Kim J. S. ; Kwon O. J. ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 52~61
In the present study, a solution algorithm for the computation of unsteady flows on unstructured meshes is presented. Dual time stepping is incorporated to achieve the second-order temporal accuracy while reducing errors associated with linearization and factorization. This allows any time step size, which is suitable for considering physical phenomena of interest. The Gauss-Seidel scheme is used to solve the linear system of equations. A special treatment based on spring analogy is made to handle meshes with high aspect-ratio cells. The present method was validated by comparing the results with experimental data and those obtained from rigid motion.
Numerical Flow Analysis of Ducted Marine Propeller with Pre-Swirl Guidevane
Yu Hye-Ran ; Jung Young-Rae ; Park Warn-Gyu ;
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 62~69
The present work solved 3D incompressible RANS equations on a rotating, multi-blocked grid system to efficiently analyze ducted marine propulsor with the interaction of propeller guidevane and annular duct. To handle the interface boundary between the guidevane and the propeller, a sliding multiblock technique based on the cubic spline interpolation was applied. To validate the present code, a turbine flow was simulated and the time-averaged pressure coefficients were compared with experiment. After the code validation, the flowfield around a ducted marine propeller with pre-swirl guidevane was simulated.
국방과학연구소 풍동실험실 소개
Journal of computational fluids engineering, volume 9, issue 2, 2004, Pages 70~74