• Particle and aerosol research
• /
• v.11 no.2
• /
• pp.47-55
• /
• 2015

This study compares the results of collection efficiency of difference gas temperature in cyclone dust collector. The previous researcher's experiment results were used to confirm the reliability of CFD(Computational Fluid Dynamics) model. Based on this verified CFD model, we extended the analysis on the cyclone dust collectors. In CFD study, we used RNG k-epsilon model for analysis of turbulence flow, fluid is air, the velocity at inlet is 10 m/s, the temperature of air is $20^{\circ}C$, $100^{\circ}C$, $200^{\circ}C$, $300^{\circ}C$, $600^{\circ}C$ and $1000^{\circ}C$. As the temperature decreases, the average velocity of outer vortex and collection efficiency is increased, showed the highest collection efficiency at $20^{\circ}C$. It can be inferred smooth flow in cyclone dust collector is difficult because air viscosity increases as temperature increases. The power required at $1000^{\circ}C$ is almost 18 times greater than that of $20^{\circ}C$ to get the similar collection efficiency.

• 한국전산유체공학회:학술대회논문집
• /
• 2006.05a
• /
• pp.225-228
• /
• 2006

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2012.11a
• /
• pp.273-275
• /
• 2012

In apartment building with column structure, reinforcing bar of the column is constructed mainly using gas pressure welding job. Therefore, gas pressure welding job in very critical process is construction apartment building with column structure. The purpose of this study is to analyze productivity of gas pressure welding work in column structure apartment using Web-CYCLONE. In this study, a CYCLONE model was developed for the productivity analysis of gas pressure welding work. Through this model, the optimal combination of the resources was obtained. This study will be utilized in the future as a useful tool of productivity analysis and the determination of an optimal combination of resources for gas pressure welding in apartment with column structure.

• International conference on construction engineering and project management
• /
• 2013.01a
• /
• pp.583-586
• /
• 2013

Construction processes are highly repetitive. A resource entity continuously cycles through work tasks that processes or uses resources. Web-CYCLONE (Halpin 1992) has been accepted as a useful tool for modeling and analyzing a specific operation. However the system has a lack of practicality as follows: (1) it does not efficiently record and keep track of operation models in a database; (2) it does not provide the functions which facilitate to retrieve corresponding model and to update local variables of the model using observed data; (3) it does not automate the complex process that executes simulation experiment, analyzes simulation outputs and generates a report on behalf of the practitioners. Therefore, practitioners have a difficulty in reusing, modifying and analyzing the existing operation models. This study introduces a Client/Server based CYCLONE that improves above-mentioned limitations in the existing Web-CYCLONE. The system was illustrated by revising CSPU in practice.

• Atmosphere
• /
• v.24 no.2
• /
• pp.207-223
• /
• 2014

The bogussing method was further developed by incorporating the asymmetric component into the symmetric bogus tropical cyclone of the Structure Adjustable Balanced Vortex (SABV). The asymmetric component is separated from the disturbance field associated with the tropical cyclone by establishing local polar coordinates whose center is the location of the tropical cyclone. The relative importance of wave components in azimuthal direction was evaluated, and only two or three wave components with large amplitude are added to the symmetric components. Using the Weather Research and Forecast model (WRF), initialized with the asymmetric bogus vortex, the track and central pressure of tropical cyclones were predicted. Nine tropical cyclones, which passed over Korean peninsula during 2010~2012 were selected to assess the effect of asymmetric components. Compared to the symmetric bogus tropical cyclone, the track forecast error was reduced by about 18.9% and 17.4% for 48 hours and 72 hours forecast, while the central pressure error was not improved significantly. The results suggest that the inclusion of asymmetric component is necessary to improve the track forecast of tropical cyclones.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1996.10a
• /
• pp.7-9
• /
• 1996

A simple two-and -half-layer model is used to study the circulation of South China Sea( SCS ). The model is coming from the reduced gravity model of Hurbult and Thompson, with the assumption of rigid surface. It shows there is no distinct branch of the Kuroshio into the SCS. Both the upper and lower pycnocline height anomaly show that the main feature of the circulation of SCS is a cyclone, which is generated by the transportion of the vorticity from the Kuroshio. Aftr generated, the cyclone moves westward due to the beta effect, then dissipates near the west boundary due to the viscosity. After an old one dissipates, a new one appears again. The life cycle of the cyclone is about 160 days.

• Proceedings of the Korean Institute of Building Construction Conference
• /
• 2021.05a
• /
• pp.149-150
• /
• 2021

Earthwork is the starting work of construction process, which has the greatest impact on the productivity of the construction project among the works. However, it is difficult to derive accurate productivity becuase the earthwork plan is affected by geological condition of the jobsite. Therefore, a simulation model for productivity analysis of earthwork was developed using CYCLONE modeling method in this study. In this paper, simulation model was made considering the impact factors of earthwork productivity. The proposed model can be utilized for sensitivity analysis in future studies.

• Proceedings of the SAREK Conference
• /
• 2008.11a
• /
• pp.546-550
• /
• 2008

In this study, 3-dimensional Computational Fluid Dynamics (CFD) analysis was induced to simulate air flow and particle motion in the axial flow cyclone separator. The commercialized CFD code FLUENT was used to visualize pressure drop and particle collection efficiency inside the cyclone. We simulated 4 cyclone models with different shape of vane, such as turning angle or shape of cross section. For the air flow simulation, we calculated the flow field using standard ${\kappa}-{\varepsilon}$ turbulence viscous model. Each model was simulated with different inlet or outlet boundary conditions. Our major concern for the flow filed simulation was pressure drop across the cyclone. For the particle trajectory simulation, we adopted Euler-Lagrangian approach to track particle motion from inlet to outlet of the cyclone. Particle collection efficiencies of various conditions are calculated by number based collection efficiency. The result showed that the rotation angle of the vane plays major roll to the pressure drop. But the smaller rotation angle of vane causes particle collection efficiency difference with different inlet position.

• Wind and Structures
• /
• v.3 no.2
• /
• pp.133-142
• /
• 2000

Engineered structures such as buildings and bridges in certain regions of the world need to be designed to withstand tropical cyclone winds, otherwise known as typhoons or hurricanes. In order to carry out this design, it is necessary to be able to estimate the maximum wind speeds likely to be encountered by the structure over its expected lifetime, say 100 years. Estimation of the maximum wind involves not only the overall strength of the tropical cyclone, but the variation of wind speed with radius from the centre, circumferential position, and with height above the ground surface. In addition, not only the mean wind speed, but also the gust factor must usually be estimated as well. This paper investigates a number of recent mathematical models of tropical cyclone structure and comments on their suitability for these purposes in a variety of scenarios.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.152-152
• /
• 2022

Only employing historical data limits the estimation of the full distribution of probable Tropical Cyclone (TC) risk due to the insufficiency of samples. Addressing this limitation, this study introduces a semi-physical TC rainfall model that produces spatially and temporally resolved TC rainfall data to improve TC risk assessments. The model combines a statistical-based track model based on the Markov renewal process to produce synthetic TC tracks, with a physics-based model that considers the interaction between TC and the atmospheric environment to estimate TC rainfall. The simulated data from the combined model are then fitted to a probability distribution function to compute the spatially heterogeneous risk brought by landfalling TCs. The methodology is employed in South Korea as a case study to be able to implement a country-scale-based vulnerability inspection from damaging TC impacts. Results show that the proposed model can produce TC tracks that do not only follow the spatial distribution of past TCs but also reveal new paths that could be utilized to consider events outside of what has been historically observed. The model is also found to be suitable for properly estimating the total rainfall induced by landfalling TCs across various points of interest within the study area. The simulated TC rainfall data enable us to reliably estimate extreme rainfall from higher return periods that are often overlooked when only the historical data is employed. In addition, the model can properly describe the distribution of rainfall extremes that show a heterogeneous pattern throughout the study area and that vary per return period. Overall, results show that the proposed approach can be a valuable tool in providing sufficient TC rainfall samples that could be an aid in improving TC risk assessment.