• Journal of Advanced Marine Engineering and Technology
• /
• v.33 no.8
• /
• pp.1180-1186
• /
• 2009

This experimental study is about the flow characteristics according to existence and nonexistence of the control rod and location in the flow field where it has the Inclined rear walls in the open cavity. By using the visualization of flow and particle image velocimetry (PIV), we performed about a change and speed of the Reynolds number. Our objective was what part of the control rod gives less effects to the characteristics of flow and how the shear mixing layer moves at what critical point of the Reynolds number. As a result, we differed the location of control rod. So finally, L/H=0.2 was discovered to give less effects to the cavity. The flow of backside of vortex faces the upper side. And we found that this phenomenon shows up more clear when the number of Reynolds increases. This is because of the flow of vortex causes by the condition of y/H=1.0. This phenomenon gets more clear with increasing of number of Reynolds, and critical point of the Reynolds number was $Re=1.0{\times}10^4$ around. If control rod is L/H=0.1, depending on the number of Reynolds ($Re=6.0{\times}10^3$, $Re=8.0{\times}10^3$, $Re=1.0{\times}10^4$, $Re=1.2{\times}10^4$), doubled vortex shows up. As the shear mixing layer of the upper side of cavity increases, the speed of the lower side was very stable.

• Korean Journal of Soil Science and Fertilizer
• /
• v.38 no.2
• /
• pp.66-71
• /
• 2005

Soil loss into stream and river by runoff shall be considered for non-point source pollution management as national land conservation. The purpose of this study was to develop the mathematical equation to predict soil loss from inclined uplands of maize cultivation due to the runoff by rainfall which mainly converges on July and August. Soil loss was concentrated on May because of low canopy over an entire field in 2002 and on June and July because of heavy rainfall in 2003. By regression analysis the relation between runoff and soil loss can be represented by a linear equation of y =1.5291x - 3.4933, where y is runoff ($Mg\;ha^{-1}$) and x is soil loss ($kg\;ha^{-1}$). The determination coefficient of this equation was 0.839 (P<0.001). Therefore, the mathematical equation derived from the practical experiment at the inclined upland can be applicable to predict soil loss accompanied by runoff due to periodic rainfall converging on short periods within a couple of months.

• Wind and Structures
• /
• v.6 no.6
• /
• pp.471-484
• /
• 2003

The rain-wind induced vibration of stays is a phenomenon discovered recently and not well explained yet. As it is influenced by a wide range of physical parameters (cable size and shape, wind speed, direction and turbulence, rain intensity, material repellency and roughness, cable weight, damping and pre-strain), this peculiar phenomenon is difficult to reproduce in laboratory controlled conditions. A successful wind tunnel experimental campaign, in which some basic physical quantities were measured, allowed an extensive analysis as to identify the parameters of the rain-wind induced excitation. The unsteady pressure field and water thickness around a cable model were measured under rainy-excited conditions. The knowledge of those parameters provided helpful information about the air-flow around the cable and allowed to clarify the physical phenomenon which produces the excitation.

• Journal of Biosystems Engineering
• /
• v.2 no.1
• /
• pp.81-84
• /
• 1977

This study was conducted to develop the leveller suitable for power tiller which has been widely used in Korea. Field test was carried out to determine its performance in accordance with the tilt angles of blede, forward velocities , and the length of blade . The results are follows ; 1. Earth moving capacity of the standard leveller was found to be 90~95kg of soil per one swath while working at the 2nd ~4th gears of forward speed. 2. Work performance of model leveller was 2 , 3, 4 times higher than manual operation in distributing additional soil of thickness 6mm , 12 mm and 24 mm on paddyland, respectively. 3. Levelling performance of model leveller on the inclined fields was 7 ~9 times higher than manual operation.

• Journal of Mechanical Science and Technology
• /
• v.17 no.10
• /
• pp.1485-1495
• /
• 2003

We investigate the triboelectrostatic separation of polyvinylchloride (PVC) from mixed plastics in the laboratory scale triboelectrostatic separation system. The flow and electric fields in the precipitator are obtained from the numerical solution of finite volume method. Using these flow and electric fields, we solved the particle motion equation considering the inertia, drag, gravity and electrostatic forces acted on the particles. The particle trajectories are obtained using a Lagrangian method as a function of different important variables such as Reynolds number, Stokes number, electrostatic force, electric charge and electric field distribution, inclined angle of plane electrodes, particle rebounding, particle charge decay rate after impact on the electrode surface, etc., in order to determine the optimal design conditions. The present predicted results for the cumulative yield represent well the experimental ones.

• 한국전산유체공학회:학술대회논문집
• /
• 2001.10a
• /
• pp.164-173
• /
• 2001

Advanced countries centered by National Supercomputing Center are inclined to construct Grid Infra and develop key applications in high performance computing field. They are also trying to globalize the Grid project aided by research groups in nations and continents. Computing technology and application development in Grid computing environment become indirect capital of high performance computing and information technology. Therefore, Korean government would like to participate in their Grid construction and application development actively and pursue to Grid project to develop Grid industries such as IT, BT. next five years.

• Structural Engineering and Mechanics
• /
• v.68 no.2
• /
• pp.215-226
• /
• 2018

In this article, the theory of fractional order two temperature generalized thermoelasticity is employed to study the wave propagation in a fiber reinforced anisotropic thermoelastic half space in the presence of moving internal heat source. The whole space is assumed to be under the influence of gravity. The surface of the half-space is subjected to an inclined load. Laplace and Fourier transform techniques are employed to solve the problem. Expressions for different field variables in the physical domain are derived by the application of numerical inversion technique. Physical fields are presented graphically to study the effects of gravity and heat source. Effects of time, reinforcement, fractional parameter and inclination of load have also been reported. Results of some earlier workers have been deduced from the present analysis.

• Journal of Biomedical Engineering Research
• /
• v.10 no.3
• /
• pp.229-236
• /
• 1989

This paper describes an idea of design and construction for a radial pulse wave detector, In acquiring arterial pulse signal noninvasively, a new combinational fiber-optic transducer was used which has a detecting part and a sensing part. The mechanism of detecting part is composed of special form of structure that can detect changing pulses in contact with skin, and transmits arterial wall movements to the sensing part. It consists of elastic reflector and optical fibers, which are arranged in a fiber pair. Then, the intensity of the reflected light will be proportional to the displacement changed by inclined reflector. Using this transducer, it expected to make a clinically useful tool for arterial pulse wave diagnosis, especially on the application of "MACK- CHIN" in the field of Korean traditional medicine, since : his transducer has a simple structure and has an easy and clear signal acquisition method.on method.

• Proceedings of the KSR Conference
• /
• 2004.06a
• /
• pp.1090-1095
• /
• 2004

Umbrella Arch Method(UAM), among others. is commonly applied to increase the facial stability during tunnel excavation and, depending on the field condition, additional reinforcement techniques can be used simultaneously. UAM, together with grouting method, is normally used to reduce ground permeability and improve stability of the tunnel by inserting a series of steel pipes into the ground around the crown inclined to the longitudinal axis of the tunnel. However. there has not been much rigorous study on the effectiveness of UAM, and most of UAM installations depend on empirical judgement rather than on engineering calculation, .In this study, the effectiveness of UAM is demonstrated based on the constitutive relationship involving UAM derived from the mechanics of composite material, and the numerical investigation is compared with small scale experiments on the tunnel reinforcement.

• Journal of computational fluids engineering
• /
• v.9 no.4
• /
• pp.64-70
• /
• 2004

A kinetic theory analysis is used to study the ultra-thin gas flow field in a gas slider bearing. The Boltzmann equation simplified by a collision model is solved by means of a finite difference approximation with the discrete ordinate method. Calculations are made for a flow in a micro-channel between an inclined slider and a moving disk drive platter The results are compared well with those from the DSMC method. The present method does not suffer from statistical noise which is common in particle-based methods and requires much less computational effort.