• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
• /
• v.33 no.5
• /
• pp.427-436
• /
• 2015

This study aims to select an optimal site for the development of small-scaled artificial ground water recharge system with the purpose of 50ton/day pumping in dry season. First of all, the topography shape satisfying the numerous factors of a hydraulic model experiment is defined and an appropriate pumping efficiency is calculated through the model experiment of injection and pumping scenario. In next step, GIS(Geographic Information System) database are constructed by processing several geospatial data to explore the optimal site. In detail, watershed images are generated from DEM(Digital Elevation Model) with 5m cell size, which is set for the minimum area of the optimal site selection. Slope maps are made from DEM to determine the optimal hydraulic gradient to procure the proper aquifer undercurrent period. Finally, the suitable site for artificial recharge system is selected using an integration of overall data, such as an alluvial map, DEM, orthoimages, slope map, and watershed images.

• Journal of Korean Society of Environmental Engineers
• /
• v.29 no.1
• /
• pp.47-53
• /
• 2007

The aim of this study is to research applicable possibility or Dry Sorbent Injection Technique(DSI) in sox removal process using Computational Fluid Dynamics(CFD) software package. It will be applied for 500MW in capacity coal-fired thermal power plant operated by South Korea N. Power Co., Ltd. The DSI process is adapted between a preheater and an EP process in the technological assembly. The numerical analysis performs in predicting and optimizing of DSI process's characteristics, which consists of structure of duct, position of injection nozzles, injection speed, and dispersion of sorbent. Computing results are shown that degree of sorbent dispersion depends on structure of duct and position of injection nozzles strongly. The highest dispersion efficiency was obtained when we set a Lobed-plate inside the duct and 6 injection nozzles on the duct(4 injection nozzles at the corners and 2 injection nozzles on upper and under walls as a rectangle duct shape). We also know that change of injection speed of sorbent doesn't have an large effect on the sorbent dispersion but it can effect to drop pressure.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.7
• /
• pp.629-636
• /
• 2010

This study is to investigate the aerodynamic effects of the Rotor-Fuselage Interactions in forward flight, and is conducted by using an improved time-marching free-wake panel method. To resolve the instability caused by the close proximity of the wake to the blade surface, the field velocity approach is added to the prior unsteady panel code. This modified method is applied to the ROBIN(ROtor Body Interaction) problem, which had been conducted experimentally in NASA. The calculated results, pressure distribution on fuselage surface and induced inflow ratio without and with the rotor, are compared with the experimental results. The developed code shows not only very accurate prediction of the aerodynamic characteristics for the rotor-fuselage interaction problem but also the rotor wake development.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.8 no.5
• /
• pp.1096-1101
• /
• 2004

The 3-D shape use to effect of movie, animation, industrial design, medical treatment service, education, engineering etc.... But it's not easy to make 3-D shape from the information of 2-D image. There are two methods in restoring 3-D video image through 2-D image; First the method of using a laser; Secondly the method of acquiring 3-D image through stereo vision. Instead of doing two methods with many difficulties, I figure out the method of simple 3-D image in this research paper. We present here a simple and efficient method, called direct calibration, which doesn't require any equations at all. The direct calibration procedure builds a lookup table(LUT) linking image and 3-D coordinates by a real 3-D triangulation system. The LUT is built by measuring the image coordinates of a grid of known 3-D points, and recording both image and world coordinates for each point; the depth values of all other visible points are obtained by interpolation.

• Journal of Korean Society of Steel Construction
• /
• v.13 no.2
• /
• pp.191-200
• /
• 2001

This paper presents buckling analysis of the cylindrical shell subjected to axial loads using numerical method. The modeling method, appropriate element type, and number of element are recommended by comparing with analytical solution. Based on the parametric study, buckling stress decreases significantly as the diameter-thickness ratio increases. These results are different from those obtained from buckling analysis of columns. The number of buckling half-wave in circumferential direction decreases as the diameter-height ratio increases. Buckling stress increases 1~2% as the thickness of base plate increases. Therefore the effect of base plate on buckling strength for cylindrical shell can be disregarded. Buckling stress significantly decreases as the amplitude of initial geometric imperfection used for calculating buckling stress is developed and it shows a good agreement with numerical results.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.38 no.3
• /
• pp.274-279
• /
• 2010

The present work is to analyze the longitudinal static stability and the drop trajectory of fighter aircraft's external fuel tank, of which horizontal fin is modified as the 20% scale down size compared with the original one. The analytical results to the pitching stability of external fuel tank using a thin airfoil's aerodynamic force data show the corresponding tendency to results of wind tunnel experiment. Results of trajectory simulation by the 6 degree of freedom equations of motion, comparing with drop trajectories of wind tunnel experiment, are shown that aircraft's attitude affects strongly on horizontal movement but not on the vertical movement. Those results give the reliability to aircraft safety when the external fuel tank with the 20% reduced horizontal fins is released from aircraft based on the flight manual.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.9 no.3
• /
• pp.207-218
• /
• 2006

The extraction of horizontal alignment and cross-section of roads is very important task in road safety diagnosis. Existing road safety diagnosis methods by investigators need much time and expense but don't provide various data. Therefor, we need road shape classification automatically and extraction method of horizontal alignment and cross-section of roads through digital photogrammetry system using GPS-VAN with laser scanner. In this paper, we propose a method of mobile laser scanning data acquisition, processing and developing extraction methods of horizontal alignment and cross-section of roads using mobile laser scanning data by GPS-VAN.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.27 no.5
• /
• pp.361-368
• /
• 2014

Modal properties for tapered cantilever pipe-type beam is identified by applying the boundary conditions to a general solution for tapered beam. A bending stiffness for cracked beam is constructed based on an energy method for tapered cantilever thin-walled pipe, which has a through-the-thickness crack, subjected to bending. Then the natural frequencies and mode shapes of a tapered cantilever thin-walled cracked pipe are identified. It can be found that the phenomenon of the bending stiffness distribution along the beam length of the cracked beam is quite reasonable, the natural frequencies are decreased as the crack sizes are increased, and the mode shapes are changed due to the crack. This results may be used to the vibration-based crack identification for the tapered cantilever pipe-type tower structures.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.9
• /
• pp.843-850
• /
• 2010

This In this paper, we describe the performance characteristics of a turbo blower as a function of the shape of the volute casing: expansion diameter and width of the volute casing. The turbo blower considered in the present study is mainly used in a refuse collection system. The flow characteristics inside the turbo blower were analyzed by a three-dimensional Navier-Stokes solver and compared with experimental results. The distributions of pressure and efficiency obtained by numerical simulation were in good agreement with those determined experimentally. Throughout the numerical simulation of the turbo blower, the blower performance was enhanced by decreasing the local losses in the blade passage and the outlet flow. The efficiency and pressure for the design flow condition were enhanced by about 3% and 2%, respectively, compared to the efficiency and pressure of the reference blower. Detailed flow analysis was performed using the results of the numerical simulation

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.7
• /
• pp.703-714
• /
• 2010

This paper describes the design optimization of a rotating rectangular channel with staggered arrays of pin-fins by Kriging metamodeling technique. Two non-dimensional variables, the ratio of the height to the diameter of the pin-fins and the ratio of the spacing between the pin-fins to the diameter of the pin-fins are chosen as the design variables. The objective function that is a linear combination of heat transfer and friction loss related terms with a weighting factor is selected for the optimization. To construct the Kriging model, objective function values at 20 training points generated by Latin hypercube sampling are evaluated by a three-dimensional Reynolds-averaged Navier-Stokes (RANS) analysis method with the SST turbulence model. The Kriging model predicts the objective function value that agrees well with the value calculated by the RANS analysis at the optimum point. The objective function is reduced by 11% by the optimization of the channel.