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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Visualization
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Journal DOI :
The Korean Society of Visualization
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Volume & Issues
Volume 9, Issue 4 - Dec 2011
Volume 9, Issue 3 - Sep 2011
Volume 9, Issue 2 - Jun 2011
Volume 9, Issue 1 - Mar 2011
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Biomedical Optics and Instrumentation Laboratory
Kim, Gi-Hyeon ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 3~9
A Study on Swirling Flow in a Vertical Circular Tube
Chang, Tae-Hyun ; O, Geon-Je ; Lee, Hae-Soo ; Kim, Sang-Youn ; Doh, Deog-Hee ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 16~23
DOI : 10.5407/JKSV.2011.9.3.016
Experiment and numerical investigation are performed on swirling water flow in a vertical circular tube. This kind of flow is used in heat exchangers, combustion chambers, thermal power plants, and other mechanical equipment to move slurries or to convey materials. However, limited information on swirling flow in vertical circular tubes is available. In the current paper, the three-dimensional particle image velocimetry(PIV) technique is employed to compare the measured velocity profiles of water along the vertical circular tube with those of non-swirl flow. In addition, computational fluid dynamics(CFD) code was applied to calculation of the flow velocities with swirl.
PIV Measurements of Ventilation Flow inside a Passenger Compartment
Lee, Jin-Pyung ; Lee, Sang-Joon ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 24~29
DOI : 10.5407/JKSV.2011.9.3.024
The improvement of climatic comfort is crucial not only for passenger comfort but also for driving safety. Therefore, a better understanding on the flow characteristics of ventilation flow inside the passenger compartment is essential. Most of the previous studies investigated the ventilation flow using Computational Fluid Dynamics (CFD) calculations or scale-down water-model experiments. In this study, the ventilation flow inside the passenger compartment of a real commercial automobile was investigated using a Particle Image Velocimetry (PIV) velocity field measurement technique. Under real operating conditions, the velocity fields were measured at several vertical planes for several ventilation modes. The experimental data obtained from this study can be used to understand the detailed flow characteristics in the passenger compartment of a real car and to validate numerical predictions.
Schlieren Visualization of the Thrust Vector Flowfield in a Supersonic Two-Dimensional Nozzle
Jeong, Han-Jin ; Choi, Seong-Man ; Chang, Hyun-Soo ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 30~37
DOI : 10.5407/JKSV.2011.9.3.030
The thrust vectoring concept has been used for use in new advanced supersonic aircraft. This study presents the performance characteristics of the thrust vectoring nozzle by visualizing the shock behaviors with Schlieren method. The scaled models were designed and manufactured to see the shock behaviors of the various airflow condition. Also we executed experimental tests to see the geometrical effects of the thrust vector nozzle by changing pitch angle and length of pitch flaps. From this study we could understand the supersonic flow characteristics of the thrust vector nozzle. The total thrust of thrust vector nozzle is diminished by increasing the flap angle. But there is an optimum flap length ratio for attaining the highest thrust level and proper pitch effect.
Prevent Air-core During Draining with Semi Spherical Mesh
Han, Eun-Su ; Park, Il-Seouk ; Sohn, Chang-Hyun ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 38~43
DOI : 10.5407/JKSV.2011.9.3.038
When draining takes place through an axially located drain port in a cylindrical tank without any prevent, a vortex with an air core occurs. In this study, semi spherical concave and convex meshes with different size inner hole are used to find the air core can suppress. The study is carried out with different values of inner hole of mesh and different install direction of semi spherical mesh using PIV and measured velocity distribution. By providing a mesh, the air core can be prevented, even if the ratio of inner hole of mesh and diameter of cylinder is around 0.66. The experimental results show that a convex mesh type is more effective to suppress the air core generation than a concave mesh type.
Study on the Fluid-Surface Characteristics by Using Flow Visualization and Numerical Simulation of Stokes Flow in a Cavity
Heo, Hyo-Weon ; Lee, Heon-Deok ; Jung, Won-Hyuk ; Cho, Dong-Sik ; Suh, Yong-Kweon ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 44~50
DOI : 10.5407/JKSV.2011.9.3.044
In this study, we propose a method for characterizing fluid-mechanical properties of a fluid surface, such as surface dilatational and shear viscosity, by matching the flow visualization and the numerical simulation for a Stokes flow in a three-dimensional cavity. The surface flow is driven by shear stress exerted on the free surface by an external gas flow. The external gas flow is simulated by using a commercial code, while the Stokes flow is calculated by an in-house code. We have found that the surface flow is very sensitive to the surface tension and other properties. The qualitative feature of the surface flow can be reproduced by the parameter tuning.
PIV Analysis on the Flows around a Cylinder under Rolling Wave
Jo, Hyo-Jae ; Doh, Deog-Hee ; Lee, Eon-Ju ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 51~58
DOI : 10.5407/JKSV.2011.9.3.051
The purpose of the study is to provide a foundation in predicting a maximum wave force when the ocean structure is laid out under breaking wave. Experiments were conducted with a down-scaled cylindrical model installed in a wave generating water channel. Maximum wave slopes were changed in regular wave condition by the wave breaker in the water channel. Cylinder's diameters were changed to 0.1m and 0.05m, respectively. Using the PIV results qualitative analyses were performed based upon the previous knowledge.
Visualization of Air Absorption Induced by Free Surface Vortex in the Pump Sump Using Multi-phase Flow Simulation
Park, Young-Kyu ; Li, Kui. Ming. ; Choi, Yoon-Hwan ; Lee, Yeon-Won ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 59~64
DOI : 10.5407/JKSV.2011.9.3.059
In this study the change of free surface vortex is expressed through the time volume fraction using multiphase unsteady condition in sump, because in previous studies of the pump sump did not represent the behavior of the free surface vortex exactly due to the reason it was calculated using single phase and steady condition. The reliability of the computational analysis is verified through comparing experimental results with that of present numerical analysis. Homogeneous free surface model is used to apply interactions of air and water. The results show that the free surface vortex can be identified on the isotropic surface at air volume fraction 1%~5%. The vortices make an air column from the free surface to the sump intake and are created and destroyed repeatedly. The behavior of free surface vortex at numerical analysis is quite similar to experimental test. The result of vortex motion according to time, works on a cycle.
Experimental and Numerical Flow Visualization on Detailed Flow Field in the Post-surgery Models for the Simulation of the Inferior Turbinectomy
Chang, Ji-Won ; Heo, Go-Eun ; Kim, Sung-Kyun ;
Journal of the Korean Society of Visualization, volume 9, issue 3, 2011, Pages 65~70
DOI : 10.5407/JKSV.2011.9.3.065
Three major physiological functions of nose can be described as air-conditioning, filtering and smelling. Detailed knowledge of airflow characteristics in nasal cavities is essential to understanding of the physiological and pathological aspects of nasal breathing. In our laboratory, a series of experimental investigations have been conducted on the airflows in normal and abnormal nasal cavity models by means of PIV under both constant and periodic flow conditions. In this work, more specifically experimental and numerical results on the surgically modified inferior turbinate model were presented. With the high resolution CT data and a careful treatment of the model surface under the ENT doctor's advice yielded quite sophisticated cavity models for the PIV experiment. Physiological nature of the airflow was discussed in terms of velocity distribution and vortical structure for constant inspirational flow. Since the inferior and middle turbinate are key determinants of nasal airflow, the turbinectomy obviously altered the main stream direction. This phenomenon may cause local changes in physiological function and the flow resistance.