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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 12, Issue 4 - Dec 2007
Volume 12, Issue 3 - Sep 2007
Volume 12, Issue 2 - Jun 2007
Volume 12, Issue 1 - Mar 2007
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COMPUTATIONS ON FLOW FIELDS AROUND A 3D FLAPPING PLATE USING THE HYBRID CARTESIAN/IMMERSED BOUNDARY METHOD
Shin, Sang-Mook ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 1~8
A code is developed using the hybrid Cartesian/immersed boundary method and it is applied to simulate flows around a three-dimensional deforming body. A new criterion is suggested to distribute the immersed boundary nodes based on edges crossing a body boundary. Velocities are reconstructed at the immersed boundary nodes using the interpolation along a local normal line to the boundary. Reconstruction of the pressure at the immersed boundary node is avoided using the hybrid staggered/non-staggered grid method. The developed code is validated through comparisons with other experimental and numerical results for the velocity profiles around a circular cylinder under the forced in-line oscillation and the pressure coefficient distribution on a sphere. The code is applied to simulate the flow fields around a plate whose tail is periodically flapping under a translation. The effects of the velocity and acceleration due to the deformation on the periodic shedding of pairs of tip vortices are investigated.
NUMERICAL ANALYSIS OF TRANSPORT PHENOMENA IN POLYMER ELECTROLYTE FUEL CELLS
Park, C.G. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 9~15
A three dimensional numerical model to predict the flow and transport of mixtures and also the electrochemical reactions in polymer electrolyte membrane (PEM) fuel cells is developed. The numerical computation is base on vorticity- velocity method. Governing equations for the flow and transport of mixtures are coupled with the equations for electrochemical reactions and are solved simultaneously including production and condensation of vapor. Fuel cell performance predicted by this calculation is compared with the experimental results and resonable agreements are achieved.
A STUDY ON CHARACTERISTICS OF AC ELECTROOSMOTIC FLOWS AND MIXING IN A MICROCHANNEL WITH COPLANAR ELECTRODES
Suh, Y.K. ; Heo, H.S. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 16~21
This paper presents numerical results of fluid flows and mixing in a microfluidic device with AC electroosmotic flows (AC-EOF) around coplanar electrodes attached on the top and bottom walls. To obtain the flow and mixing characteristics, numerical computations are performed by using a commercial code, CFX10. Experiment was performed to confirm the generation of the drift velocity around the electrodes. It was found that near the coplanar electrodes 3-D complex flows are generated. The AC-electroosmotic flow on the electrodes plays an important role in mixing the liquid.
AUTOMOBILE UNDERHOOD THERMAL AND AIR FLOW SIMULATION USING CFD
Oh, K.T. ; Kim, J.H. ; Lee, S.W. ; Kim, Y.S. ; Ha, J.W. ; Kang, W.K. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 22~27
Automobile underhood thermal and airflow simulation h α s been performed by using a commercial CFD program, FLUENT. To implement the radiation heat transfer effect to the underhood thermal and flow field, Discrete Ordinates Method(DOM) was used. The cooling fan was modeled by using the Multiple Reference Frame(MRF) technique. For the implementation of the heat exchangers, such as radiator and condenser, which are located in the front side of vehicle, the effectiveness-NTU model was used. The pressure drop throughout the heat exchangers was modeled as Porous media. For the validation of the current computational method, the coolant temperature at the inlet port of the radiator was compared with experimental data, and less than 3% error was observed. Finally, the composed model was used for the cooling fan spec determination process in the development of a new vehicle, and the results showed that the current CFD method could be successfully applied to the vehicle development process.
NUMERICAL STUDY ON THE OPTIMAL DESIGN OF SPRAY SYSTEM IN PACKED BED SCRUBBER
Ko, S.W. ; Ro, K.C. ; Ryou, H.S. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 28~34
This study evaluates the performance of the packed bed scrubber and proposes the optimization of spray system for improvements of collection efficiency. The packed bed scrubber is used primarily in the semiconductor manufacturing process. The mean diameter of entering solid particles in scrubber is the submicron. The impaction between water droplets and solid particles is an important factor in removing the solid particles. Thus, the coverage area of spray system influences on the collection efficiency. The collection efficiency of a single droplet is calculated through the mathematical model and numerical calculations are performed for coverage area for each nozzle type (Droplet diameters: 500, 319.5,
) and injected directions (0, 15,
). In case of nozzle type 3, the collection efficiency of a single droplet is highest but the collection efficiency of spray system has lowest value because the ratio of flow rate between the gas and water is below 0.1. The results show the coverage area ratio is about 85% in the case of nozzle type 3 and downward sirection
. It was shown that a coverage area increase by two times than an existing spray system. In simulation of demister, collection efficiency by demister is predicted about 80% and the pressure drop in demister is below 3.5 Pa.
INCOMPRESSIBLE FLOW COMPUTATIONS USING A HERMITE STREAM FUNCTION
Kim, J.W. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 35~42
This paper describes a recent development on the divergence free basis function based on a hermite stream function and verifies its validity by comparing results with those from a modified residual method known as one of stabilized finite element methods. It can be shown that a proper choice of degrees of freedom at a node with a proper arrangement of the hermite interpolation functions can yield solenoidal or divergent free interpolation functions for the velocities. The well-known cavity problem has been chosen for validity of the present algorithm. The comparisons from numerical results between the present and the modified residual showed the present method yields better results in both the velocity and the pressure within modest Reynolds numbers(Re = 1,000).
COMPARATIVE STUDY ON FLUX FUNCTIONS AND LIMITERS FOR THE EULER EQUATIONS
Chae, E.J. ; Lee, S. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 43~52
A comparative study on flux functions for the 2-dimensional Euler equations has been conducted. Explicit 4-stage Runge-Kutta method is used to integrate the equations. Flux functions used in the study are Steger-Warming's, van Leer's, Godunov's, Osher's(physical order and natural order), Roe's, HLLE, AUSM, AUSM+, AUSMPW+ and M-AUSMPW+. The performance of MUSCL limiters and MLP limiters in conjunction with flux functions are compared extensively for steady and unsteady problems.
NUMERICAL STUDY ON THE FREQUENCY CHARACTERISTICS OF SCREECH TONE IN A SUPERSONIC JET
Kim, Yong-Seok ; Ryu, Ki-Wahn ; Hwang, Chang-Jeon ; Lee, Duck-Joo ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 53~59
An axisymmetric supersonic screeching jet is numerically simulated to examine the length scales of screech frequency as well as screech tone generation mechanism. The axisymmetric Reynolds-averaged Navier-Stokes equations in conjuction with a modified Spalart-Allmaras turbulence model are employed. It is demonstrated that the axisymmetric jet screech tones can be simulated correctly and the numerical results are in good agreement with the experimental data. Instability waves, shock-cell structures and the phenomena of shock motion are investigated in detail to identify the screech tone generation mechanism. Shock spacings and standing wave length are analyzed to determine the dominent length scale crucial to the screech frequency formulation.
A ROBUST SCHEME FOR THE MULTICOMPONENT REACTIVE GAS FLOWS IN THE PRESENCE OF SHOCK WAVES
Hu, Z.M. ; Myong, R.S. ; Cho, T.H. ;
Journal of computational fluids engineering, volume 12, issue 1, 2007, Pages 60~67
In this paper, the dispersion controlled dissipative (DCD) scheme is reviewed and then extended to simulate chemically reacting gas flows in multicomponent mixtures in the presence of strong shock waves. Furthermore, the properties of the reactive DCD (DCD-R) scheme are discussed, followed by several applications. The DCD scheme has been shown to have the following features: high accuracy and robustness for reacting gas flows in the presence of strong shock waves and contact discontinuities, and algorithmic simplicity.