• Title/Summary/Keyword: Surface Height

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A Study on Verticle Structure of the Urban Boundary Layer (도시 경계층의 연직구조에 관한 연구)

  • 이상득;오은주
    • Journal of Environmental Science International
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    • v.5 no.3
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    • pp.285-295
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    • 1996
  • In genneral, Businger expression is used for determining a turbulance diffusion coefficient. In this study, it is applied to the surface elements of cities such as Asphalt, Cround, Grass, Pond. We set up 5 m-height bar and measured the ary temperature and wet temperature at 도 height of 0.13, 0.27, 0.5, 1, 0, 3.0, 5.0m. In addition we measured the wind gradient and wind velocity at the height 3 m solar radiation continuously for 48 hours on the surface. Compared the measured data to Businger expression the result showed that Businger expression can be well applied to the complex surface of the city.

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Cusp Height in Circular Surface Machining Using Ball End Mill (볼엔드밀을 이용한 원호곡면의 가공시 CUSP의 크기)

  • Yoon, Hee-Jung;Park, Sang-Lyang;Choi, Jong-Soon;Park, Dong-Sam
    • Proceedings of the KSME Conference
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    • 2000.04a
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    • pp.826-830
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    • 2000
  • Sculptured surface machining plays a vital role in the process of bring new Products to the market place. A great variety of products rely on this technology for the production of the dies and moulds used in manufacturing. And, the use or CNC machines and CAD/CAM system has become a vital parts or product development process. But, cusp is inevitable by-product in sculptured surface machining, and it is very difficult to calculate the cusp height correctly. In this study, an analytical cusp height model is proposed considering the radius of the ball end mill, radius of machined workpiece and the inclined angle of convex or concave circular surface. Experiments were performed to check the validity of this proposed model and experimental results showed that the proposed cusp model were very effective.

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Effect of Tip Clearance Height on Heat Transfer Characteristics on the Plane Tip Surface of a High-Turning Turbine Rotor Blade (팁간극이 고선회각 터빈 동익 평면팁 표면에서의 열전달에 미치는 영향)

  • Moon, Hyun-Suk;Lee, Sang-Woo
    • 유체기계공업학회:학술대회논문집
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    • 2005.12a
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    • pp.173-177
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    • 2005
  • The heat/mass transfer characteristics on the plane tip surface of a high-turning first-stage turbine rotor blade has been investigated by employing the naphthalene sublimation technique. The heat/mass transfer coefficient is measured for four tip clearance height-to-chord ratios of h/c = 1.0%, 2.0%, 3.0%, and 4% at the Reynolds number of $2.09{\times}105$. The result shows that at lower h/c, there exists a strong flow separation/re-attachment process, which results in severe thermal load along the pressure-side comer. As h/c increases, the re-attachment is occurred further downstream of the pressure-side comer with lower thermal load. At higher h/c, a pair of vortices on the tip surface near the leading edge are found along the pressure-side and suction-side comers, and the pressure-side tip vortex have significant influence even on the mid-chord local heat transfer.

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A Study on the Behavior of Liquid Free Surface in a Shaking Vessel (진동교반조에서의 액자유표면의 거동에 관한 연구)

  • Lee, Young-Sei;Kim, Moon-Gab
    • Journal of the Korean Society of Industry Convergence
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    • v.3 no.3
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    • pp.209-217
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    • 2000
  • An attempt has been made to examine the highest liquid surface by means of measuring the movement of liquid free surface wave in the agitated vessel wall. Also, Relationship has been investigated between transition frequency, $N_z$ for behavior of liquid free surface and transition frequency for behavior of mass transfer coefficient in the agitated vessel wall. A surface wave is occured within agitated vessel, the highest height of wetted vessel wall, $h_w$ is coincided with the highest liquid surface, h. However the lowest height of wetted vessel, $h^*{_w}$ is not descended to lowest liquid free surface, $h^*$. The proposed model has been tested sucessfully for the behavior of liquid free surface.

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Physics-based height map optimization conveying real-measured flow speed for virtual soap bubble rendering

  • Han, Sol;Yoo, Sangwook;Chin, Seongah
    • International Journal of Advanced Culture Technology
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    • v.8 no.3
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    • pp.284-290
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    • 2020
  • In this paper, we propose a method to generate and optimize the height map that is suitable to render a soap bubble. The height map represents the flow speed of soap bubbles. To this end, we have analyzed the flow of the soap bubble surface through experiment, derived the moving speed value for each section. Some image filters have been used for optimization that reflects the parameters of the derived height map. In addition, in order to verify the results of the study, actual data measuring the surface flow speed of soap bubbles, the speed of the initial height map, and the optimized height map speed have been compared and tested. Through this study, we reach the issue that it is possible to express the variable flow speed of soap bubbles with the optimized height map, and it will help to express various fluids.

Study on the two-dimensional Formation Control of Free Surface of Magnetic Fluid by Electromagnetic Force (전자기력에 의한 자성유체의 2차원 자유표면 형상 제어에 관한 연구)

  • 안창호;지병걸;이은준;박명관
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2003.06a
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    • pp.979-982
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    • 2003
  • In this study, because of change in electromagnetic force, deformation of the free surface motion of a magnetic fluid is changed. Deformation of the free surface motion of a magnetic fluid for the change in electromagnetic force is discussed and carried out theoretically and experimentally on the basis of Rosensweig Ferrohydrodynamic Bernoulli Equation. Objective of this study explicates free surface motion by electromagnetic force and planes to designed controller. To control free surface of magnetic fluid, it embody designed two-dimensional free surface form of magnetic fluid. By using this characteristics, they applied to oscillator for surface control, flow control, boundary layer control. Strength of magnetic field and height of free surface of magnetic fluid measure as a hall-effect sensor. As performing height control of magnetic fluid, the result will be presented possibility of free surface deformation control.

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The Relationship of the Body Surface Development Figure with the Sleeve Basic Pattern in the Standing and Arm-Movement Positions (정립시 및 동작시 팔의 체표면 전개도와 소매원형의 관계)

  • Cho, Kyunghee
    • Journal of Fashion Business
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    • v.17 no.1
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    • pp.170-185
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    • 2013
  • The suitability of the pattern manufactured with the development figure was considered by reviewing the development conditions that can be directly connected to the basic pattern in the human body surface development figure with the cast bandage method. The method to prepare the sleeve basic pattern was based on the cylindrical surface development method, and the sleeve basic pattern covering the 45 and 90 degrees momentum of the arm-movement was made by using the cast-type body surface development figure prepared with the horizontal line of the sleeve hem placed horizontally in the plan and by combining the cast-type body surface development figure in the standing position with the figure in the moving position. The test clothing was prepared with the sleeve pattern adding the bodice pattern in the standing position and the momentum and was worn on the FRP replica. The relationship theory of the body surface development figure with the pattern was derived by reviewing the suitability from the wearing state. The sleeve-cap height of the sleeve basic pattern resulted in about 80% in the standing position when the needs for a physical activity are 45 degrees and the about 50% when the needs for a physical activity are 90 degrees. The additional size of the diagonal length of the sleeve-cap could be set as "0" if the sleeve-cap height is low by 50% and as 50% of the additional size in the standing position if the sleeve-cap height is 80%.

A Study on the Effective Free Surface of Fluid Cargo (유동화물의 유효자유표면에 관한 연구)

  • Hur, I.;Wang, J.S.
    • Journal of the Korean Institute of Navigation
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    • v.11 no.2
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    • pp.73-88
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    • 1987
  • It is well known that the height of tank metacenter above the centroid of fluid in a tank is given by i/v where I is the inertia moment of free surface and v is the fluid volume. It is supposed in this formula that the inclination of ship is small and that the free surface of fluid do not touch the top and the bottom of tank. It the inclination of ship is large, the height of tank metacenter may be possibly greater than that given by i/v. The height of tank metacenter is smaller than i/v when the free surface of fluid touch the top or the bottom of tank. The reasonable method to calculate the height of tank metacenter is presented in this paper and prepared in FORTRAN program by FUNCTION EFFRES. The approximate formula was also developed and given by $g_m=(1+\frac{2}{1}tan^2\theta)[1-EXP\{-12(\frac{\alpha(1-\alpha)k}{tan\theta})^{1.25}\}]\frac{i}{v}$ where $g_m$ is the distance from the centroid of fluid to the tank metacenter, $\theta$ is inclined angle of ship, $\alpha$ is the ratio of filled volume to tank capacity and k is the ratio of the depth to the width of tank. The values calculated by the approximate formula given in this paper were compared with the exact values from the computer program and proved out to be sufficiently precise for practical use.

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