• Proceedings of the KSME Conference
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• 2004.04a
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• pp.1522-1527
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• 2004

The purpose of this study is to investigate the effect of swirler angle and swirl chamber aspect ration of nozzle on the characteristics of single and twin spray. The performances of nozzle has been investigated by measurements of spray angle, droplet size, velocity and Weber number at a water pressure 0.4MHz. Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the smaller swirler angle, the larger axial velocity became. It was also shown that the larger aspect ratio, the smaller droplet diameter became.

• Journal of Environmental Science International
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• v.4 no.1
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• pp.29-40
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• 1995

Transport rate of windblown dusts such as soil, sand, snow is proportionate to $U*_^3 and U_*$, friction velocity, approximately to flow velocity of ink Therefore, through measurement and the flow velocity of wind, it turned out that, considering different velocity distributions caused by downstream distance and porosity percent, windbreaks with appropriate porosity rate to the Protection area should be chosen for the optimal fence effect. In the economic respects better are fences with gap of 20%~30%. Among the windbreaks to have the optimal fence effect.

• Journal of applied mathematics & informatics
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• v.41 no.2
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• pp.401-411
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• 2023

The effects of longitudinal velocity dusty fluid flow in a weak magnetic field are investigated in this paper. An external uniform magnetic field parallel to the flow of dusty fluid influences the flow of dusty fluid. Besides that, the problem under investigation is completely defined in terms of identifying parameters such as longitudinal velocity (u), Hartmann number (M), dust particle interactions β, stock resistance γ, Reynolds number (Re) and magnetic Reynolds number (Rm). While using suitable transformations of resemblance, The governing partial differential equations are transformed into a system of ordinary differential equations. The Hankel Transformation is used to solve these equations numerically. The effects of representing parameters on the fluid phase and particle phase velocity flow are investigated in this analysis. The magnitude of the fluid particle is reduced significantly. The result indicates the magnitude of the particle reduced significantly. Although some of our numerical solutions agree with some of the available results in the literature review, other results differs because of the effect of the introduced magnetic field.

• Journal of Advanced Marine Engineering and Technology
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• v.18 no.5
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• pp.24-28
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• 1994

In the present paper, the behavior of bubbles in a fluidized bed has been investigated experimentally. The bubble size, distribution of bubble, bubble rising velocity and pressure fluctuation in the fluidized bed are obtained at different air velocity. The results are discussed and compared study the effect of air velocity on the behavior of a bubbles in fluidized bed.

• Journal of Korean Physical Therapy Science
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• v.17 no.3_4
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• pp.51-58
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• 2010

Purpose: The purpose of this study was to examine changes of postural sway between the normal group and treatment group of same people through COP movements. Methods: Fifty men with no history of sensory, neurological and orthopedic disorders were participated in this study. Participants were tested on single limb balance during 30 seconds on EMED system with bared foot. Each of them performed two methods and 5 trials totally each method: (1) non-treated group (2) treated group(with big toe flexion limitation). Data on the moving length, average velocity, instantaneous maximum velocity, mediolateral(x axis) maximum velocity, and anteroposterior(y axis) maximum velocity of COP were measured in single limb standing position. Results: The moving length and average velocity of COP were significant difference between normal and treatment group(p<0.05). On correlation of parameters, the faster average velocity of COP, the higher moving length, instantaneous maximum velocity, mediolateral maximum velocity, and anteroposterior maximum velocity of COP increase. The more Instantaneous maximum velocity of COP, the faster is anteroposterior maximum velocity of COP. Conclusions: Limitation of big toe flexors function affected single limb balance of the normal.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.308-311
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• 2005

In this paper, we studied about the effects of the rotating cantilever pipe conveying fluid with a moving mass. The influences of a rotating angular velocity, the velocity of fluid flow and moving mass on the dynamic behavior of a cantilever pipe have been studied by the numerical method. The equation of motion is derived by using the Lagrange's equation. The cantilever pipe is modeled by the Euler-Bemoulli hew theory. When the velocity of a moving mass is constant, the lateral tip-displacement of a cantilever pipe is proportional to the moving mass and the angular velocity. In the steady state, the lateral tip-displacement of a cantilever pipe is more sensitive to the velocity of fluid than the angular velocity, and the axial deflection of a cantilever, pipe is more sensitive to the effect of a angular velocity.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.385-391
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• 2000

Velocity method was supposed by Parkin et al.(1985) in order to supplement previous log t and (equation omitted) method. This study was to present the method for estimating the horizontal coefficient of consolidation by using velocity method which was based on the Barren's equation. Velocity method throughly eliminated not only settlement curve which had shape with difficulty in evaluating coefficient of consolidation but also the effect of unknown intial compression, the secondary consolidation and occurrence of unknown point by using velocity instead of settlement. The purpose of this study is to investigate its application in field. Velocity method was used in obtaining horizontal coefficient of consolidation in Kyung-gi area. Horizontal coefficient of consolidation using velocity method was calculated and compared with log t method, √t method Magnan & Deroy's method, Bergado's method.

• Journal of the Korean Society of Safety
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• v.8 no.2
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• pp.44-50
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• 1993

The objective of this study was to investigate the extraction of chromium(Vl) ion in waste water through the liquid surfactant membrane with open-type Perforated Reciprocating-Plate Column. Extraction experiments were conducted to measure the effect of flow characteristics of continuous and dispersed phase and stroke velocity, sodium hydroxide concentraction in internal aqueous phase, sulfuric acid concentraction in outer phase, and residence time distribution and measured extraction velocity. The result of experiments showed that extraction velocity of chromium ion was maximum when stroke velocity was 180 1/min and dispersion phase velocity was 30m11min, continuous phase velocity was 20m1/min. Extraction velocity of chromium ion increased with increasing difference of hydrogen ion concentraction of dispersion and continuous phase and column stage decreased.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.11
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• pp.990-997
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• 2005

The stratified effect was investigated with three different types of diffuser shape in a thermal storage tank with variation of diffuser diameter, velocity, Froude number etc. Its effect was estimated by the degree of stratification. No matter of diffuser diameter and shape, the degree of stratification was the best as the Froude number gets closer to 1. In the case of a curved diffuser, when its diameter is a quarter of tank diameter and ejection velocity in a diffuser is approximately 0.2 m/s, the Froude number was almost 1. In the case of a flatted diffuser, when ejection velocity was 0.05 m/s, the Froude number was 1.5. Both cases which Froude number were nearer 1, showed the good degree of stratification.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.36 no.12
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• pp.848-855
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• 1987

The currents in the rails of an electromagnetic railgun are concentrated in a near surface region. In order to understand this phenomenon, this paper deals with computation of the current distribution related to skin effect in a railgun. An analytical solution is obtained for a twodimensional model. It is found that current concentration at the interface between the rails and the armature is affected by the velocity, length and conductivity of the armature, that skin effect in the rails is affected by the relative velocity between the rails and the armature rather than other factors, and that skin depth in the rails is inversely proportional nearly to the square root of the velocity.