• Title/Summary/Keyword: Spreading force

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Effect of Frictional Resistance Force on a Liquid Pool Spreading Model with Continuous and Instantaneous Release (마찰저항이 연속누출과 순간누출을 가지는 액체 풀의 확산에 미치는 영향에 대한 해석적 연구)

  • Kim, Tae Hoon;Choi, Byung-Il;Kim, Myungbae;Do, Kyu Hyung;Han, Yong-Shik
    • Journal of Hydrogen and New Energy
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    • v.24 no.6
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    • pp.487-494
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    • 2013
  • In this study, solutions for a liquid pool spreading model with continuous and instantaneous release are discussed based on the model used in the FERC's report. The effects of the release time on the liquid pool volume and radius are investigated for the continuous release. For the continuous release with the frictional resistance force in the liquid pool spreading model, the vaporization time decreases as the release time increases. On the other hand, for the continuous release without the frictional resistance force in the liquid pool spreading model, the vaporization time increases as the release time increases. These phenomena are deeply related to the pool radius. In addition, the effects of the initial pool radius for the instantaneous release in the liquid pool spreading model are discussed. For the case with the frictional resistance force in the liquid pool spreading model, as reducing release time in the model with the frictional resistance force for the continuous release, the solution for a continuous release approaches to that for an instantaneous release. On the contrary to this, the pool volume and radius for the instantaneous release without the frictional resistance force are totally different from those for the continuous release without the frictional resistance force.

Estimation of vertical and horizontal spreading force of the towing cage for transporting the live fish by model test and simulation (모형실험과 시뮬레이션을 통한 활어 이송용 예인 가두리의 수직 및 수평 전개력 추정)

  • Park, Subong;Lee, Chun Woo
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.50 no.2
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    • pp.176-184
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    • 2014
  • Nowadays, consumption of fisheries products is increasing. There are several factors, one of which is a quantitative development through aquaculture. Another factor is an increase qualitative consumption of fish which require that fish be supplied alive. This requires a lot of technical effort to transport the live fish that have low survival rate (c.f. tuna and mackerel) in coastal waters and in the open sea. To develop a towing cage for transporting the live fish, model test in a circulate water channel and simulation by computer tool were carried out. In order to spread vertically, floats were attached at the upper part of the cage, and iron chains attached at the lower part of the cage. For horizontal spreading, kites were attached on the cage. The tension and spreading performance of the cage were measured. The result shows that the tension and reduction ratio of inside volume of the cage were tended to increase with increased towing speeds. The suitable operation condition in towing cage was 1.0 m/s towing speeds with vertical spreading force 8.7 kN, horizontal spreading force 5.6 kN; in this case the reduction ratio of inside volume of the cage was estimated as 25%.

Experimentally Evaluation of a Liquid Pool Spreading Model with Continuous Release (연속누출을 가지는 액체 풀 확산 모델의 실험적 평가)

  • KIM, TAEHOON;DO, KYU HYUNG;KIM, MYUNGBAE;HAN, YONG-SHIK;CHOI, BYUNG-IL
    • Journal of Hydrogen and New Energy
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    • v.26 no.6
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    • pp.659-665
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    • 2015
  • In this study, an experimental investigation is performed for evaluation of a liquid pool spreading model with continuous release. The model considered in this study was developed based on a concept which means that the liquid pool spreading is governed by a balance between an inertia force from gravity and a frictional force from friction with the ground under the whole base of the liquid pool. For evaluation of the model, experimental study is performed. Experimental apparatus is setup for measuring release rate, spreading velocity, and evaporation rate from a liquid pool. The experimental results are compared with results from the model. By applying release and evaporation rates obtained from experiments to solving the model, liquid pool radius variation according to time can be obtained. For evaluation of an effect of friction force in the spreading model, results obtained from the models with and without the friction force are compared with those obtained from the experiments. As a result, it is shown that there exists a large deviation between the results obtained from the model without the friction force and the experimental results. On the other hand, the tendency of liquid pool radius variation according to time is similar between the results obtained from the model without the friction force and the experimental results.

DEVELOPMENT OF A NUMERICAL TECHNIQUE FOR CAPILLARY SPREADING OF A DROPLET CONTAINING PARTICLES ON THE SOLID SUBSTRATE (미세입자분산 액적의 고체면에서 모세퍼짐 현상에 관한 직접수치해석 기법개발)

  • Hwang, Wook-Ryol;Jeong, Hyun-Jun;Kim, See-Jo;Kim, Chong-Youp
    • Journal of computational fluids engineering
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    • v.12 no.4
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    • pp.14-19
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    • 2007
  • We present a direct numerical simulation technique and some preliminary results of the capillary spreading of a droplet containing particles on the solid substrate. We used the level-set method with the continuous surface stress for description of droplet spreading with interfacial tension and employed the discontinuous Galerkin method for the stabilization of the interface advection equation. The distributed Lagrangian-multipliers method has been combined for the implicit treatment of rigid particles. We investigated the droplet spreading by the capillary force and discussed effects of the presence of particles on the spreading behavior. It has been observed that a particulate drop spreads less than the pure liquid drop. The amount of spread of a particulate drop has been found smaller than that of the liquid with effectively the same viscosity as the particulate drop.

Timing Driven Placement using Force Directed Method and Optimal Interleaving Technique (포스 디렉티드 방법과 최적 인터리빙 기법을 이용한 타이밍 드리븐 배치)

  • Sung Young-Tae;Hur Sung-Woo
    • Journal of KIISE:Computer Systems and Theory
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    • v.33 no.1_2
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    • pp.92-104
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    • 2006
  • The proposed method for a force directed global placement algorithm exploits and extends techniques from two leading placers, Kraftwerk (& KraftwerkNC) and Mongrel. It combines the strengths of KraftwerkNC, force directed global placer, and Mongrel's ripple move technique which resolves cell overlaps effectively The proposed technique uses the force spreading technique used in Kraftwerk to optimize the ripple movement. While it is resolving the cell overlap and optimizing wire length physical net constraints are considered for timing. The experimental results obtained by the proposed approach shows significant improvement on wire length as well as on timing.

DEVELOPMENT OF A NUMERICAL TECHNIQUE FOR IMPACT AND SPREADING OF A DROPLET CONTAINING PARTICLES ON THE SOLID SUBSTRATE (미세입자분산 액적의 고체면에서 충돌과 퍼짐현상에 관한 직접수치해석 기법개발)

  • Jeong, Hyun-Jun;Hwang, Wook-Ryol;Kim, Chong-Youp
    • Journal of computational fluids engineering
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    • v.13 no.3
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    • pp.8-13
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    • 2008
  • We present a numerical simulation technique and some preliminary results of the impact and spreading of a droplet containing particles on the solid substrate in 2D. We used the 2nd-order Adams-Bashforth / Crank-Nicholson method to solve the Navier-Stokes equation and employed the level-set method with the continuous surface stress for description of droplet spreading with interfacial tension. The impact velocity has been generated by the instantaneous gravity. The distributed Lagrangian-multipliers method has been combined for the implicit treatment of rigid particles and the discontinuous Galerkin method has been used for the stabilization of the interface advection equation. We investigated the droplet spreading by the inertial force and discussed effects of the presence of particles on the spreading behavior using an example problem. We observed reduced oscillation and spread for the particulate droplet.

Origin of the East Sea (Japan Sea) and Plate Tectonics (東海의 起源과 板構造論)

  • Kim, So Gu
    • 한국해양학회지
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    • v.19 no.1
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    • pp.94-102
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    • 1984
  • The origin of the East sea is discussed in the light of modern geophysical theories such as plate tectonics and sea-floor spreading. The origin of the East Sea was due to the tensional force of the back-arc spreading which was initiated as early as late Cretaceous time of Paleocene. The spreading was asymmetric with a fast movement of eastward or southeastward and a slow westward motions. The spreading, however, was confined to the East Sea due to the change of the Pacific Plate north-northwest to west-northwest during Eocene time. Further intensifying research based on more accurate seismic data as well as on geophysical and geological informations should be carried out continuously to understand if the spreading of the Japan Sea died out due to triple junction formed by mention of the Pacific, the Eurasian, and the Philippine plates since the Quaternary.

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Study on Prediction for Prompt Countermeasures to Oil Spread in Ocean (해안기름유출사고에 의한 기름확산 예측 방법 연구)

  • Kim, Young-Bok
    • Journal of Ocean Engineering and Technology
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    • v.25 no.2
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    • pp.108-112
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    • 2011
  • When oil spills occur in the ocean because of a ship collision or grounding, the oil in the sea will spread to the coastline. To effectively and promptly prevent such an oil spread, the prediction of the direction and speed of the spreading oil must be made. By applying the coastal wave diffusion theory with a consideration of the effects of wind and current, the oil spreading direction and speed can be predicted promptly so that the National Disaster Prevention System can effectively and promptly take countermeasures against the attack and contamination of the coastline by such oil bands.

Natural Frequency Analysis of Spring-Manipulator System for Force Generation Utilizing Mechanical Resonance

  • Kobayashi, Jun;Ohkawa, Fujio
    • 제어로봇시스템학회:학술대회논문집
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    • 2005.06a
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    • pp.1651-1656
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    • 2005
  • This paper describes a natural frequency analysis conducted to find out a suitable working area for a spring-manipulator system generating a large vibrating force with mechanical resonance. Large force generation is one of the functions that we hope for a robot. For example, a weeding robot is required to generate a large force, because some weeds have roots spreading deeply and tightly. The spring-manipulator system has a spring element as an end-effector, so it can be in a state of resonance with the elasticity of the spring element and the inertial characteristics of the manipulator. A force generation method utilizing the mechanical resonance has potential to produce a large force that cannot be realized by a static method. A method for calculating a natural frequency of a spring-manipulator system with the generalized inertia tensor is proposed. Then the suitable working area for the spring-manipulator system is identified based on a natural frequency analysis. If a spring-manipulator system operates in the suitable working area, it can sustain mechanical resonance and generate a large vibrating force. Moreover, it is shown that adding a mass at the tip of the manipulator expands the suitable working area.

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Cutting Characteristics of Plasma Source Son Implanted Tungsten Carbide Tool (플라즈마 이온주입에 의해 표면 개질한 초경공구의 가공특성)

  • Kang, Seong-Ki;Wang, Duck-Hyun;Kim, Won-Il
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.1
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    • pp.33-40
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    • 2010
  • In this research, the effects for surface Improvement of plasma ion implanted carbide endmill tools were observed by measuring cutting forces and tools wear affecting surface roughness in high speed cutting. From the 2nd ion mass analysis, the oxidation layer was found to be built up by sputtering. The residual gas contamination of oxygen was found to be contained impurities in nitrogen gas. The plasma implanted ion was found to be spreaded, especially the nitrogen was implanted up to 150nm depth as impressed voltage and ion implanting time. It is analyzed as bring surface improvement by spreading deeply forming oxidation on surface. The factors in Analysis of Variance(ANOVA) about mutuality cause reference of cutting force. The cutting force Fx is affected by the interaction of spindle rpm and federate, the cutting force Fy is influenced by spindle rpm and time injected ion, and cutting force Fz is affected by the interaction of impressed voltage and feedrate. Also, it was found that the cutting forces of implanted tools become lower and the surface roughness is improved by the effect of nitrogen according to the implantation.