• Title/Summary/Keyword: Magnus Effect

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Numerical Analysis Study on the Turbulent Flow Characteristics around the Rotor Sail for Vessels (선박용 로터세일 주위의 난류 유동특성에 관한 수치해석적 연구)

  • Kim, Jung-eun;Cho, Dae-Hwan;Lee, Chang-Yong
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.28 no.4
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    • pp.648-656
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    • 2022
  • As environmental regulations such as the International Maritime Organization (IMO)'s strategy to reduce greenhouse gases(GHG) are strengthened, technology development such as eco-friendly ships and alternative fuels is expanding. As part of this, ship propulsion technology using energy reduction and wind propulsion technology is emerging, especially in shipping companies and shipbuilders. By securing wind propulsion technology and introducing empirical research into shipbuilding and shipping, a high value-added market using eco-friendly technology can be created. Moreover, by reducing the fuel consumption rate of operating ships, GHG can be reduced by 6-8%. Rotor Sail (RS) technology is to generate a hydrodynamic lift in the vertical direction of the cylinder when the circular cylinder rotates at a constant speed and passes through the fluid. This is called the Magnus effect, and this study attempted to propose a plan to increase propulsion efficiency through a numerical analysis study on turbulence flow characteristics around RS, a wind power assistance propulsion system installed on a ship. Therefore, CL and CD values according to SR and AR changes were derived as parameters that affect the aerodynamic force of the RS, and the flow characteristics around the rotor sail were compared according to EP application.

The Action of Panaquilon on the Isolated Clam Heart (Panaquilon의 적출조개 심장운동에 대한 작용)

  • Song, Suk-Kyu
    • The Korean Journal of Pharmacology
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    • v.6 no.1
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    • pp.9-13
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    • 1970
  • The effect of Panaquilon (Partial Component of Panax ginseng), on the isolated clam heart, the motility of the isolated clam heart suspended in physiological solution for clam heart was recorded by the Magnus Method. 1. The concentration of $5{\times}10^{-6}$ of Panaquilon produced cardiac arrest in the diastolic state, which resumed the normal state slowly after changing the physiological solution for clam heart. 2. Cardiac arresting action of Panaquilon was antagonistic when pretreated with Serotonin.

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The Action of Panaquilon on the Isolated Rabbit Uterus (Panaquilon의 적출토끼자궁운동에 대한 작용)

  • Song, Suk-Kyu;Park, Chung-Soon
    • The Korean Journal of Pharmacology
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    • v.5 no.2
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    • pp.129-133
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    • 1969
  • The effect of the panaquilon (partial component of panax ginseng), on the isolated pregnant and nonpregnant uterus strip was observed. The movement of the strip of the rabbit uterus suspended in Locke's solution was refolded by the Magnus method. 1. The tonus of the pregnant uterus was slightly increased and returned the normal movement after a short period (approximately 60 seconds) in concentration of $10^{-6}$ of panaquilon. 2. The tonus and motility of panaquilon was slightly synergistic when pretreated with syntocinon and barium chloride.

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3D 플라잉 디스크의 회전 운동에 따른 비정상 유동 해석

  • Park, Da-Un;Kim, Tae-Uk
    • Proceeding of EDISON Challenge
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    • 2016.11a
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    • pp.4-8
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    • 2016
  • 본 연구에서는 플라잉 디스크를 이용하여 회전 운동의 유무에 따른 공력특성의 변화를 비교 분석하였다. 회전 운동이 발생하면 표면에 비대칭적으로 압력이 분포하기 때문에 롤링 모멘트가 발생하고 마그너스 효과로 측력이 발생하고 피칭모멘트, 회전감쇠모멘트가 발생하고 롤 안정성이 증가한다.

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The Effect of ${\gamma}-Aminobutyric$ Acid on the Intestinal Motility of Rabbit (${\gamma}-Aminobutyric$ Acid가 토끼 장관운동에 미치는 영향)

  • Lee, Kae-Yurl;Lee, Myung-Hi;Jung, Hyung;Lim, Kyu-Parl
    • The Korean Journal of Physiology
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    • v.1 no.1
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    • pp.51-56
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    • 1967
  • In order to find out the effects of GABA on the rabbit's intestinal motility, the following experiments were carried out using Magnus method and the results obtained were as follows: 1. GABA inhibited the intestinal motility of rabbits initially. 2. GABA potentiated the inhibitory action of adrenaline and nor-adrenaline. 3. GABA inhibited the accelerating activity of acetylcholine on the intestinal motility by its anti acetylcholine effect. 4. The inhibitory action of GABA was unaffected with atropinization, strychnin, picrotoxin treatment, but the accelerating activity of GABA observed in some cases was only in the picrotoxin treatment.

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On the modification of particle dispersion in isotropic turbulence by free rotation of particle (등방성 난류에서 입자의 회전에 의한 분산 특성의 변화)

  • Park, Yong-Nam;Lee, Chang-Hoon
    • Proceedings of the KSME Conference
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    • 2008.11b
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    • pp.2554-2557
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    • 2008
  • Effect of a particle's spin is investigated numerically by considering the effect of lift occurring due to difference of rotations of a particle and of fluid such as the Saffman lift and Magnus force. These lift forces have been neglected in many previous works on particle-laden turbulence. The trajectory of particles can be changed by the lift forces, resulting in significant modification of the stochastic characteristics of heavy particles. Probability density functions and autocorrelations are examined of velocity, acceleration of solid particle and acceleration of fluid at the position of solid particle. Changes in velocity statistics are negligible but statistics related with acceleration are a little bit changed by particle's rotation. When a laden particle encounters with coherent structures during the motion, the particle's rotation might significantly affects the motion due to intermittently large fluid acceleration near coherent structures.

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A Study on NADPH-Diaphorase and Neuropeptide Y-Positive Neurons in The Brain Stem of Aged Rats (노화된 흰쥐의 뇌줄기에 분포하는 NADPH-Diaphorase 및 Neuropeptide Y양성 신경세포에 관한 연구)

  • Kim, Soon-Hee;Chang, Hwan-Il;Huh, Young-Buhm;Ahn, Hee-Kyung
    • Korean Journal of Biological Psychiatry
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    • v.3 no.2
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    • pp.191-202
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    • 1996
  • This study was aimed to charily the change of NADPH-diaphorase(NADPH-d) and neuropeptide Y(NPY) associated with aging of the rots. To verily the effect of aging of NPY and NADPH-d-positive neurons in the brain stem, the neurons were stained by the immunohistochemical and histochemical method. In the aged group, the number of NADPH-d-positive neurons was significantly decreased in substantia nigra lateralis, supragenual nucleus, raphe magnus nucleus and raphe obscurus nucleus as compared with control group. The number of NADPH-d-positive neurons was not significantly decreased in superior colliculus, interpeduncular nucleus, central gray. dorsal raphe nucleus, retrorubral nucleus, pedunculopontine tegmental nucleus, laterodorsal tegmental nucleus, pontine reticular nucleus, prepositus hypoglossal nucleus and nucleus solitarius of the aged rats. The NADPH-d and NPY-positive neurons were found in the interpeduncular nucleus, central gray, substantia nigra lateralis, laterodorsal tegmental nucleus, nucleus solitarius, raphe magnus nucleus, raphe obscurus nucleus of the control and aged groups. The coexistence of NADPH-d and NPY in the some cell was not found in the brain stem of both groups.

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The Magnus Effect of a Rotating Circular Cylinder near a Plane Wall (벽면근처에서 회전하는 원주의 마그너스 효과)

  • Ro, Ki-Deok;Kim, Kwang-Seok
    • 한국가시화정보학회:학술대회논문집
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    • 2006.12a
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    • pp.42-47
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    • 2006
  • The flow around a rotating circular cylinder near a plane wall is investigated by the measurement of the lift acting on the cylinder and by the flow visualization using the hydrogen bubble technique in the circulating water tank. The experimental parameters are the rotating direction of the cylinder, the space ratios H/D$(H/D=0.05\sim0.5)$ between cylinder and plane wall and the velocity ratios $\alpha(\alpha=0\sim{\pm}2.0)$. In the case of clockwise, the lift on the rotating circular cylinder was increased with the reduction of the space ratios and with the velocity ratios, the upper separation point was more shifted in the rotating direction with them. In the case of anticlockwise, the absolute value of the lift on the rotating circular cylinder was increased with the space ratios and with the velocity ratios, the lower separation point was more shifted in the rotating direction with them.

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On wave propagation of football ball in the free kick and the factors affecting it

  • Xumao Cheng;Ying Wu
    • Steel and Composite Structures
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    • v.46 no.5
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    • pp.669-672
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    • 2023
  • In this research, the researcher has examined the factors affecting the movement of the soccer ball and will show that the effects such as air resistance, altitude above sea level, wind, air pressure, air temperature, air humidity, rotation of the earth, changes in the earth's gravitational acceleration in different areas. It, the geographical length and latitude of the launch point, the change of gravitational acceleration with height, the change of pressure with height, the change of temperature with height and also the initial spin (Magnus effect) affect the movement of projectiles (especially soccer ball). We modelled th ball based on shell element and derive the motion equations by energy method. Finally, using numerical solution, the wave of the ball is studied. The influences of various parameters are investigated on wave propagation of the ball. Therefore, in short, it can be said that the main factors that play a major role in the lateral deviation of the hit ball are the initial spin of the ball and the wind.

Numerical Simulation on Laminar Flow past a Rotating Circular Cylinder (회전하는 원형 실린더 주위 층류유동장의 수치 시뮬레이션)

  • Park, Jong-Chun;Moon, Jin-Kook;Yoon, Hyun-Sik;Lee, Byung-Hyuk;Chun, Ho-Hwan;Suh, Sung-Bu
    • Journal of Ocean Engineering and Technology
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    • v.19 no.3
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    • pp.1-10
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    • 2005
  • The effect of rotation on the unsteady laminar flaw past a circular cylinder is numerically investigated in the present study. The numerical solutions for the 2D Navier-Stokes equation obtained, using two different numerical methods. One is an accurate spectral method and the other is a finite volume method(FVM). First, the flaw around a stationary circular cylinder is investigated to understand the basic phenomenon of flaw separation and bluff body wake. Next, the flow characteristics of the laminar flow, past a rotating circular cylinder, are investigated, using a FVM developed in this study. By the effect of rotation, it is seen that values of lift increase, while the values of mean drag decrease. Further, the criteria of angular velocity, at which the Karman vorteces disappear, is also determined.