• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.1355-1360
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• 2009

This study simulates the flow characteristics of the turbo-fan which was applied to the industrial scale. Numerical analysis has been carried out to investigate a pulsation behavior of exhaust air that flow out the turbo fan, considering a constant rotating rate of impeller. Moving mesh technique provides time-accurate solutions for the flow inside an impeller. From the numerical results, FFT analysis has been made for pressure pulsations inside turbo-fan casing. The numerical simulation shows the pulsation of model-2 has higher than model. Additionally, BPF value is almost same as the numerical results.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2103-2108
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• 2007

This study investigates the dynamic characteristics of Synchronous Reluctance Motor (SynRM), with segmental rotor structure, using finite element method in which the moving mesh technique is considered. The focus of this paper is the efficiency of on-line parameter identification system for position sensorless control of a SynRM considering saturation and iron loss. Comparisons are given with angle of the observer and those of proposed FEM & Preisach model of synchronous reluctance motor, respectively. The position sensorless control using identified motor parameters is realized, and the efficiency of the on-line parameter identification system is verified by experimental results.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.673-674
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• 2006

This study investigates the dynamic characteristics of Synchronous Reluctance Motor (SynRM), with segmental rotor structure, using finite element method in which the moving mesh technique is considered. The focus of this paper is the sensorless vector control parameters estimation of SynRM under saturation and iron loss. Comparisons are given with dynamic characteristics of normal single B-H nonlinear solutions and those of proposed FEM & Preisach model of synchronous reluctance motor, respectively.

• The KSFM Journal of Fluid Machinery
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• v.10 no.6
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• pp.24-31
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• 2007

In the present study, the effects of the design factors and operating conditions on flow characteristics of a vane pump for the automotive power steering system has been analyzed numerically. An unsteady moving mesh technique with cell expansion/contraction method is used to simulate the rotation of vanes with respect to stationary inlet and outlet. As a result, the flow characteristics of the flow rate and pressure rise across the vane pump were obtained. The numerical analyses for the various design factors such as number of vanes and thickness between the rotor and camring and for various operating conditions such as rotational speed and pressure difference between inlet and outlet were extensively performed. And the results were discussed in the paper.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.316-318
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• 1998

This paper describes the direct thrust control of permanent magnet linear synchronous motor (PMLSM) with the secondary aluminium sheet. The time stepped finite element method and moving mesh technique are used for simulating dynamic characteristics of the PMLSM. The secondary back-iron conductivity as well as the initial flux linkage due to permanent magnet are considered in the simulation.

• 한국전산유체공학회:학술대회논문집
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• 1999.05a
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• pp.35-47
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• 1999

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 consist 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 demonstate the effectiveness and parallel performance of this procedure.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1001-1002
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• 2007

This study investigates the dynamic characteristics of Synchronous Reluctance Motor (SynRM), with segmental rotor structure, using finite element method in which the moving mesh technique is considered. The focus of this paper is the efficiency of on-line parameter identification system for position sensorless control of a SynRM under saturation and iron loss. Comparisons are given with angle of the observer and those of proposed FEM & Preisach model of synchronous reluctance motor, respectively. The position sensorless control using identified motor parameters is realized, and the effective of the on-line parameter identification system is verified by experimental results.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.7-9
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• 1998

In this paper, dynamic characteristics analysis of linear induction motor with joints in the secondary conductor is discussed. The time stepped finite element method and moving mesh technique are used for simulation. ${\nabla}{\phi}$ of jointed secondary conductor is defined for simulation, respectively. Simulation results have shown that joints in the secondary conductor affect thrust ripple and attractive force ripple.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.1
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• pp.39-45
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• 2005

In the situation which Russia's ratification of the Kyoto protocol at February,2004, ANNEX I nations must reduce GHG(Green House Gas) discharge rate from 2008 by 2012 to the reduction level at 1990. We introduce the CO₂ ocean sequestration that is one of promising method for getting the stable CO₂ concentration in the atmosphere. There are four categories : ocean transportation technique, ocean initial dissolution technique, ocean deep current evaluation technique, and ocean biological evaluation technique. In this paper, we carried out the fundamental numerical study on the ocean initial dissolution technique, when the Liquidized CO₂ is emitted at the deep ocean, It is very important to the dissolution rate of movable CO₂ interface because it Is directly impact to the ocean organism. In order to investigate the relation of the interface movement and rate of the dissolution, we develope CR(Computational Fluid Dynamics) code that was constructed by the finite volume method based on the unstructured mesh, and a droplet's boundary surface can move and one direction dissolution from disperse phase into continuous phase adopted as its physics be. This study clarifies hydrodynamic relation between solubility and movement of the droplet through the verification of the Cm code.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.5
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• pp.409-418
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• 2014

Simulation of flow past a complex marine structure requires a fine resolution in the vicinity of the structure, whereas a coarse resolution is enough far away from it. Therefore, a lot of grid cells may be wasted, when a simple Cartesian grid system is used for an Immersed Boundary Method (IBM). To alleviate this problems while maintaining the Cartesian frame work, we adopted an Adaptive Mesh Refinement (AMR) scheme where the grid system dynamically and locally refines as needed. In this study, We implemented a moving IBM and an AMR technique in our basic 3D incompressible Navier-Stokes solver. A Volume Of Fluid (VOF) method was used to effectively treat the free surface, and a recently developed Lagrangian Dynamic Subgrid-scale Model (LDSM) was incorporated in the code for accurate turbulence modeling. To capture vortex induced vibration accurately, the equation for the structure movement and the governing equations for fluid flow were solved at the same time implicitly. Also, We have developed an interface by using AutoLISP, which can properly distribute marker particles for IBM, compute the geometrical information of the object, and transfer it to the solver for the main simulation. To verify our numerical methodology, our results were compared with other authors' numerical and experimental results for the benchmark problems, revealing excellent agreement. Using the verified code, we investigated the following cases. (1) simulating flow around a floating sphere. (2) simulating flow past a marine structure.