• Title, Summary, Keyword: Migration velocity

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Hydrodynamic interaction between two cylinders in planar shear flow of viscoelastic fluid

  • Jung, Hyun-Wook;Daejin Won;Kim, Chongyoup
    • Korea-Australia Rheology Journal
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    • v.14 no.4
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    • pp.203-207
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    • 2002
  • Particle-particle interaction is of great importance in the study of suspension rheology. In this research we have investigated the hydrodynamic interaction between two identical cylinders in viscoelastic fluids numerically as a model problem for the study of viscoelastic suspension. We confine two neutrally buoyant cylinders between two parallel plates and impose a shear flow. We determine the migration velocity of two cylinders. The result shows that cylinders move toward or away from each other depending upon the initial distance between them and that there is an equilibrium distance between two cylinders in viscoelastic fluids regardless of the initial distance. In the case of Newtonian fluid, there is no relative movement as expected. The results partly explain the chaining phenomena of spherical particles in shear flows of viscoelastic fluids.

Fluoride Migration of Frozen Antarctic Krill According to Thawing Methods (해동방법에 의한 냉동크릴의 불소이동)

  • Kim, Kil-Hwan;Kim, Dong-Man;Kim, Young-Ho;Yoon, Hye-Hyun
    • Korean Journal of Food Science and Technology
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    • v.22 no.2
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    • pp.168-171
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    • 1990
  • This study was purposed to elucidate the migration phenomenon of fluoride from the chitinous sections into the muscle flesh of the frozen krill during thawing. The fluoride content ratio between chitinous sections and muscle flesh in the frozen krill was 94.8 : 5.2. Among the several thawing methods used, migration velocity of fluoride was the highest in the krill thawed with microwave and the lowest in the krill thawed at low temperature $(4^{\circ}C)$. The migrated amount of fluoride after thawing was various depended upon the thawing methods, and the increased amount during thawing was 2-5 times higher than Initial amount before thawing.

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Multicomponent RVSP Survey for Imaging Thin Layer Bearing Oil Sand (박층 오일샌드 영상화를 위한 다성분 역VSP 탐사)

  • Jeong, Soo-Cheol;Byun, Joong-Moo
    • Geophysics and Geophysical Exploration
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    • v.14 no.3
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    • pp.234-241
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    • 2011
  • Recently, exploration and development of oil sands are thriving due to high oil price. Because oil sands reservoir usually exists as a thin layer, multicomponent VSP, which has the advantage of the high-resolution around the borehole, is more effective than surface seismic survey in exploring oil sand reservoir. In addition, prestack phase-screen migration is effective for multicomponent seismic data because it is based on an one-way wave equation. In this study, we examined the applicability of the prestack phase-screen migration for multicomponent RVSP data to image the thin oil sand reservoir. As a preprocessing tool, we presented a method for separating P-wave and PS-wave from multicomponent RVSP data by using incidence angle and rotation matrix. To verify it, we have applied the developed wavefield separation method to synthetic data obtained from the velocity model including a horizontal layer and dipping layers. Also, we compared the migrated image by using P-wave with that by using PS-wave. As a result, the PS-wave migrated image has higher resolution and wide coverage than P-wave migrated image. Finally, we have applied the prestack phase-screen migration to the synthetic data from the velocity model simulating oil sand reservoir in Canada. The results show that the PS-wave migrated image describe the top and bottom boundaries of the thin oil sand reservoir more clearly than the P-wave migrated image.

Prediction of Leachate Migration from Waste Disposal Site to Underground LPG Storage Facility and Review of Contamination Control Method by Numerical Simulations (수치모의를 통한 지하 LPG 저장시설에 인접한 폐기물매립지에서의 침출수이동 예측 및 제어공법 검토)

  • 한일영;서일원;오경택
    • Journal of the Korean Society of Groundwater Environment
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    • v.3 no.2
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    • pp.51-59
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    • 1996
  • In case waste disposal site is to be constructed close to the underground facilities such as LPG storage cavern which is completely maintained by groundwater pressure, it is generally requested that the possibility on leachate contamination of cavern area be reviewed and the countermeasure, if it is estimated cavern area is severely affected by leachate, be taken into consideration. Prediction was performed and leachate control plan was made using by analytical and the numerical analysis on the leachate migration which is likely to happen at the area between the proposed waste disposal site and the underground LPG storage cavern located at the U petrochemical complex. Analytical solutions were obtained by the conservative mass advection-diffusion equation and the effect of advection and dispersion factor on the leachate migration was reviewed through peclet number calculation and the functional relationship between the factors and leachate transport velocity was established, which leads to enable us to predict the leachate transport velocity without difficulties when different parameters (factors) are used for analytical solution. Numerical solutions were obtained by FEM using AQUA2D which is for the simulation of groundwater flow and contaminant transport. 3-D discrete fracture models were simulated and fracture flow analysis was performed and feasibility study on the water-curtain system was conducted through the fracture connectivity analysis in rock mass. As results of those analyses, it was interpreted that the leachate would trespass on the LPG storage cavern area in 30 years from the proposed wate disposal site and the vertical water-curtain system was effective mathod for the prevention of leachate's migration further into the cavern area.

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Refraction traveltime tomography using damped monochromatic wavefield

  • Pyun, Suk-Joon;Shin, Chang-Soo
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.441-448
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    • 2003
  • Refraction tomography requires an algorithm for efficiently computing the traveltimes and their $Fr\'{e}chet$ derivatives. We have attempted to solve the damped wave field using the frequency domain finite element model ing and then invoked the reciprocity theorem to calculate the $Fr\'{e}chet$ derivative of the traveltime with respect to the subsurface parameter. Then, we used a damped least square method to invert the traveltimes of the Marmousi 2 model. Numerical tests demonstrate that the refraction tomography with large aperture data can be used to estimate the smooth velocity model for the prestack depth migration.

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Analytic Solution of Electrostatic Precipitator′s Collection Efficiency for Polydisperse Aerosol (다분산 에어로졸에 대한 전기집진 효율의 해석해)

  • 정창훈;박현설;이규원
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • pp.297-298
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    • 2002
  • 전기집진기(ESP)는 보일러, 소각로등 많은 산업 공정에서 발생되는 입자상 물질을 제거하는데 일반적으로 사용되어 왔다. 가장 널리 쓰이는 ESP의 집진효율을 예측하기 위한 수식으로는 Deutsch-Anderson식으로 다음과 같다.(equation omitted) 여기서 η는 포집효율, Ac는 집진판의 표면적(surface area), Ve는 전기집진기 내 입자의 유효 이동속도(effective migration velocity), 그리고 Q는 단위면적을 통과하는 가스의 부피 유량이다. (중략)

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Evaluation of Electrokinetic Flow Mobility Using Isotacho-Electrophoresis Techniques

  • An, J.H.;Joo, Y.H.;Lee, C.Y.;Lee, Y.J.;Park, C.W.
    • Journal of Magnetics
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    • v.16 no.4
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    • pp.444-448
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    • 2011
  • In the present study, we separated the marker particles from the suspending particle mixture solution using isotacho-electrophoresis technique, a novel quantitative ionic particle separation method, in the microchannel. A multiple stacking zone of the suspending particle was visualized with variations in electric field strength, pH value and concentration of the ionic solution. In particular, the electrophoretic mobility of ionic particle (fluorescein) was estimated based on the electrophoretic velocity value measured by the particle image velocimetry. As a result, isotacho-electrophoresis zones were clearly visualized as going downstream in the electric field. The particle migration velocity increased proportional to the applied voltage increase; it was also affected by the pH value variations in the ionic solution.

DNA Separation Chips Using Asymmetrically-Switched Nonuniform Electric Fields (비대칭 교차전기장의 불균일 분포를 이용한 DNA 분리 소자)

  • Yi, So-Yeon;Cho, Young-Ho
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.33 no.3
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    • pp.265-268
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    • 2009
  • We present the experimental study to realize a DNA separation chip using asymmetrically-switched nonuniform electric fields. The DNA separation chip redistributes DNA molecules within a specific area based on the size- and field-dependent nonlinearity of DNA drift velocity. The present chip is composed of a width variable channel to distribute nonuniform electric field, a DNA loading slit and a pair of electrodes to apply electric field. We focus on the design of DNA separation chips with identifying the nonlinearity of DNA drift velocity using three different DNA molecules (11.1kbp, 15.6kbp, and 48.5kbp) in the chips. It is demonstrated that different size of DNA shows different net migration in different direction under the asymmetrically-switched nonuniform electric field.

A Study on the Migration Characteristics of Cs-137 in a Packed Column (충전층에서의 세슘-137의 이동특성에 관한 연구)

  • Lee, Jae-Owan;Cho, Won-Jin;Han, Kyung-Won;Park, Hun-Hwee
    • Nuclear Engineering and Technology
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    • v.22 no.1
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    • pp.20-28
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    • 1990
  • In this study the migration experiment using packed column with crushed tuff was conducted as a basic research to develop migration model of radionuclides through geologic media. The main emphasis was put on evaluating the validity of migration models. For this, two models were introduced: one is the model which is based on the assumption of instantaneous equilibrium reaction and the other the model based on kinetic process such as intraparticle diffusion. The coefficient of hydrodynamic dispersion in packed column was determined using iodine as nonsorbing tracer. The hydrodynamic dispersion coefficient, D$_{L}$ was shown to be 0.11$\times$10$^{-2}$ $\textrm{cm}^2$/min under the condition of the column porosity of 0.483 and the average water velocity of 0.915$\times$10$^{-2}$ cm/min. The distribution coefficient, Kd of Cs-137 on crushed tuff was 11.3 cc/g at the concentration of 2$\times$10$^{-6}$ M and the temperature of 2$0^{\circ}C$. The breakthrough curve of Cs-137 through packed column was shown to have an asymmetric curve in which long trailing tail appears at the end part of the curve. The results obtained from the comparison of introduced models with experimental data indicated that the mass transfer model with intraparticle diffusion as rate-controlling step simulated the behaviors of Cs-137 migration more adequately, when compared with the bulk reaction model in which the assumption of instantaneous equilibrium reaction was maded. Consequently, the intraparticle diffusion was found to be an important factor in the migration of Cs-137 through packed column.n.

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A Study of Waveform Inversion for Improvement of Sub-Salt Migration Image (암염돔 하부 구조의 구조보정 영상 개선을 위한 파형역산 기법 연구)

  • Ha, Wan-Soo;Pyun, Suk-Joon;Son, Woo-Hyun;Shin, Chang-Soo;Ko, Seung-Won;Seo, Young-Tak
    • Geophysics and Geophysical Exploration
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    • v.11 no.3
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    • pp.177-183
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    • 2008
  • The sub-salt imaging technique becomes more crucial to detect the hydro-carbonates in petroleum exploration as the target reservoirs get deeper. However, the weak reflections from the sub-salt structures prevent us from obtaining high fidelity sub-salt image. As an effort to overcome this difficulty, we applied the waveform inversion by implementing multi-grid technique to the sub-salt imaging. Through the comparison between the conventional waveform inversion using fixed grid and the multi-grid technique, we confirmed that the waveform inversion using multi-grid technique has advantages over the conventional fixed grid waveform inversion. We showed that the multi-grid technique can complement he velocity estimation result of the waveform inversion for imaging the sub-salt structures, of which velocity model cannot be obtained correctly by the conventional fixed grid waveform inversion.