• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2002년도 추계 학술대회논문집
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• pp.28-34
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• 2002

A computational study of supersonic flow around lateral jet controlled missile has been performed. For this study, three dimensional Navier-Stokes code(AADL3D) has been developed. Spalart-Allmaras one equation turbulence model has been implemented on the AADL3D code for relatively rapid computational time. For the validation of developed code, AADL3D, pressure distributions on an ogive-cylinder body has been compared with experimental data. Also, the shock structure of sonic jet on the flat plate in the supersonic flow field has been compared with experimental flow visualization result to see the analysis capability of freestream-jet interaction case. A case study has been performed through comparing the normal force coefficient and the moment coefficient of missile body for several jet flow conditions. Current results will be used to the optimum design of a lateral jet controlled missile.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2002년도 봄 학술발표회 논문집
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• pp.413-420
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• 2002

Recent experimental research results of connection method between steel pipe pile and concrete footing are provided based on various experimental observations. It gives a shedding light toward developing better and concrete connection method for steel pipe pile at the field application. In this study, the newly developed method is tested for compressive, pull put and combination load including moment with carefully designed monitoring system. The measured data show that new method have at least equivalent or better load resistant capacities compared with those of specified method in Korea Highway Corporation design code. It is also tried to define and investigate the load transfer mechanism for new method.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권2호
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• pp.60-65
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• 2005

This study tries to analyzes the static friction torque that generated in a micro-electromagnetic clutch by using FEM. For the purpose of design change and optimization of the micro-electromagnetic clutch, the static friction torque prediction is very important. We construct the axi symmetric FEM model for analyze the static friction torque and the real material properties are substituted to the FEM model. For a test, predicted static friction torque is compared with experimental one to discuss the rationality of torque analysis process. The analytical result agrees well to experimental data. explaining the validity of the mathematical process and FEM model.

• Nuclear Engineering and Technology
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• 제36권2호
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• pp.165-174
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• 2004

The distributed resistance model has been recently implemented into the MATRA-LMR code in order to improve its prediction capability over the wire-wrap model for a flow blockage analysis in the LMR. The code capability has been investigated using experimental data observed in the FFM (Fuel Failure Mock-up)-2A and 5B for two typical flow conditions in a blocked channel. The predicted results by the MATRA-LMR with a distributed resistance model agreed well with the experimental data for wire-wrapped subchannels. However, it is suggested that the parameter n in the distributed resistance model needs to be calibrated accurately for a reasonable prediction of the temperature field under a low flow condition. Finally, the analyses of a blockage for the assembly of the KALIMER design are performed. Satisfactory results by the MATRA-LMR code were obtained through and rerified a comparison with results of the SABRE code.

• 한국산업융합학회 논문집
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• 제3권4호
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• pp.353-360
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• 2000

The purpose of this research is to find the fundamental data for the design and optimum operation condition for the disk atomization comparing the atomization characteristics of the modified straight vane type disk atomizer and the cup type atomizer widely used in the field of spray dry. First, the experimental comparison of the characteristics of $Na_2SO_4$ atomization has been carried out using the cup type disk atomizer and the three kinds of vane type atomization designed specially for the experiment. After the comparison of the experimental data of the $Na_2SO_4$ and raw milk have been conducted using vane type atomizer.

• Wind and Structures
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• 제16권6호
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• pp.629-660
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• 2013

This paper reviews the current state-of-the-art in the numerical evaluation of wind loads on buildings. Important aspects of numerical modeling including (i) turbulence modeling, (ii) inflow boundary conditions, (iii) ground surface roughness, (iv) near wall treatments, and (vi) quantification of wind loads using the techniques of computational fluid dynamics (CFD) are summarized. Relative advantages of Large Eddy Simulation (LES) over Reynolds Averaged Navier-Stokes (RANS) and hybrid RANS-LES over LES are discussed based on physical realism and ease of application for wind load evaluation. Overall LES based simulations seem suitable for wind load evaluation. A need for computational wind load validations in comparison with experimental or field data is emphasized. A comparative study among numerical and experimental wind load evaluation on buildings demonstrated generally good agreements on the mean values, but more work is imperative for accurate peak design wind load evaluations. Particularly more research is needed on transient inlet boundaries and near wall modeling related issues.

• 한국초전도ㆍ저온공학회논문지
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• 제10권4호
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• pp.13-17
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• 2008

This paper presents experimental and characteristic analysis of hgh-$T_c$ eater-triggered witch using coated conductor (CC) in liquid and gas helium. The high temperature superconducting insert coil which can be installed in a low temperature superconducting (LTS) magnet has been proposed and researched to generate higher magnetic field for MR. Since CC could be an attractive option for HTS insert, it is important to research he characteristics of heater-triggered switch employing CC. We performed the heater test and constructed simulation model using finite element method (FEM.) We performed a protection test and observed normal zone propagation (NZP) signals to evaluate the witch with protection of magnet.

• Nuclear Engineering and Technology
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• 제56권2호
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• pp.410-418
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• 2024

Study of flow behavior within rod bundles has been an active topic. Surface modification technologies are important parts of the design of the fourth generation reactor, which can increase the strength of the secondary flow within the rod bundle lattices. Quasi-periodic large-scale vortex structure (QLVS) is introduced by arranging micro ribs on the surface of rod bundles, which enhanced the scale of the secondary flow between the rod bundle lattices. Using computational fluid dynamics (CFD) and water experiments, the flow field distribution and drag coefficient of the rod-bundle lattices are studied. The secondary flow between the micro-ribbed rod-bundle lattice is significantly enhanced compared to the standard rod-bundle lattice. The numerical simulation results agree well with the experimental results.

• 로봇학회논문지
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• 제13권3호
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• pp.151-156
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• 2018

Military robots are expected to play an important role in the future battlefield, and will be actively engaged in dangerous, repetitive and difficult tasks. During the robots perform the tasks a human operator controls the robots in a supervisory way. The operator recognizes battlefield situations from remote robots through an interface of the operator control center, and controls them. In the meantime, operator workload, controller interface, robot automation level, and task complexity affect robot operability. In order to assess the robot operability, we have developed ROSim (Robot Operational Simulator) incorporating these operational factors. In this paper, we introduce the results of applying ROSim experimentally to the assessment of reconnaissance robot operability in a battle field. This experimental assessment shows three resulting measurements: operational control workload, operational control capability, mission success rate, and discuss its applicability to the defense robot research and development. It is expected that ROSim can contribute to the design of an operator control center and the design analysis of a human-robot team in the defense robot research and development.

• Design & Manufacturing
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• 제6권2호
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• pp.48-53
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• 2012

In previous study, it showed that the MAP was greatly effective polishing process for magnesium plate. But it had lower efficiency than magnetic materials such as SM45C. It was very difficult to cut non-magnetic materials using the MAP process because the process was fundamentally possible by help of a magnetic force. This study aimed to verify analytically formation of the magnetic field in a case of the non-magnetic materials especially focused on magnesium plate. So, In this study, the magnetic density flux was predicted using simulation program. As a result, the magnetic density flux was lower at the center of pole on inductor than outside. It had same result on the experimental verification. And magnetic force was lower according to increase of working gap. So, to improve the magnetic force, permanent magnet was installed under the workpiece. In that case, the magnetic density flux not only at center but also at outside of pole was increased. Therefore, the efficiency of magnetic abrasive polishing was also increased. A design of experimental method was adopted for assessment of parameters' effect on the MAP results of magnesium plate for improving the magnetic force.