• Title/Summary/Keyword: movement distribution

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Wind-sand coupling movement induced by strong typhoon and its influences on aerodynamic force distribution of the wind turbine

  • Ke, Shitang;Dong, Yifan;Zhu, Rongkuan;Wang, Tongguang
    • Wind and Structures
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    • v.30 no.4
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    • pp.433-450
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    • 2020
  • The strong turbulence characteristic of typhoon not only will significantly change flow field characteristics surrounding the large-scale wind turbine and aerodynamic force distribution on surface, but also may cause morphological evolution of coast dune and thereby form sand storms. A 5MW horizontal-axis wind turbine in a wind power plant of southeastern coastal areas in China was chosen to investigate the distribution law of additional loads caused by wind-sand coupling movement of coast dune at landing of strong typhoons. Firstly, a mesoscale Weather Research and Forecasting (WRF) mode was introduced in for high spatial resolution simulation of typhoon "Megi". Wind speed profile on the boundary layer of typhoon was gained through fitting based on nonlinear least squares and then it was integrated into the user-defined function (UDF) as an entry condition of small-scaled CFD numerical simulation. On this basis, a synchronous iterative modeling of wind field and sand particle combination was carried out by using a continuous phase and discrete phase. Influencing laws of typhoon and normal wind on moving characteristics of sand particles, equivalent pressure distribution mode of structural surface and characteristics of lift resistance coefficient were compared. Results demonstrated that: Compared with normal wind, mesoscale typhoon intensifies the 3D aerodynamic distribution mode on structural surface of wind turbine significantly. Different from wind loads, sand loads mainly impact on 30° ranges at two sides of the lower windward region on the tower. The ratio between sand loads and wind load reaches 3.937% and the maximum sand pressure coefficient is 0.09. The coupling impact effect of strong typhoon and large sand particles is more significant, in which the resistance coefficient of tower is increased by 9.80% to the maximum extent. The maximum resistance coefficient in typhoon field is 13.79% higher than that in the normal wind field.

Centrifuge Model Experiments for Lateral Soil Movements of Piled Bridge Abutments. (교대말뚝기초의 측방유동에 관한 원심모형실험)

  • Choi, Dong-Hyurk;Jeong, Gil-Soo;Park, Byung-Soo;Yoo, Nam-Jae
    • Journal of Industrial Technology
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    • v.25 no.B
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    • pp.63-71
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    • 2005
  • This paper is an experimental result of investigating lateral soil movements at piled bridge abutments by using the centrifuge model facility. Three different centrifuge model experiments, changing the methods of ground improvement at bridge abutment on the soft clayey soil (no improvement, preconsolidation and plastic board drains (PBD), sand compaction pile (SCP) + PBD), were carried out to figure out which method is the most appropriate for resisting against the lateral soil movements. In the centrifuge modelling, construction process in field was reconstructed as close as possible. Displacements of abutment model, ground movement, vertical earth pressure, cone resistance after soil improvement and distribution of water content were monitored during and after centrifuge model tests. As results of centrifuge model experiments, preconsolidation method with PBD was found to be the most effective against the lateral soil movement by analyzing results about displacements of abutment model, ground movement and cone resistance. Increase of shear strength by preconsolidation method resulted in increasing the resistance against lateral soil movement effectively although SCP could mobilize the resistance against lateral soil movement. It was also found that installment with PBD beneath the backfill of bridge abutment induced effective drainage of excess pore water pressure during the consolidation by embanking at the back of the abutment and resulted in increasing the shear strength of clay soil foundation and eventually increasing the resistance of lateral soil movement against piles of bridge abutment.

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Effect of Breathing on Ground Reaction Force and Kinematic Variables dur ing Bending in Korean Dance (호흡에 따른 한국무용 굴신동작이 운동학적 변인과 지면반력에 미치는 영향)

  • Park, Yang-Sun
    • Korean Journal of Applied Biomechanics
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    • v.21 no.3
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    • pp.327-334
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    • 2011
  • The objective of this study was to develop a scientific approach for investigating Korean dance in detail, and to examine the intense expressions and various movements, which are based on Danjeon breathing. For the purpose, we analyzed the movement changes and distribution of forces resulting from the switch in movement between exhalation and inhalation while bending, which is the most basic movement in Korean dance. The following conclusions were drawn from this study. In Korean dance, bending with breathing involves less back-and-forth-movement and more up-and-down movement, as compared to bending without breathing; this indicates greater body stability and a wider range of movements while bending with breathing. In addition, less time is required for bending with breathing at the point of switching from exhalation to inhalation, and it involves less movement of the supporting leg; thus, vending with breathing involves faster switching from bending movements to extending movements. While bending, the raised leg goes through a less smooth curve while breathing, which indicates stronger movement of the toes. Bending with breathing requires a greater braking force than bending without breathing, and the vertical force, generated by switching from exhalation to inhalation, is transferred to extending movements using the ground load. The results of this study can be potentially employed to investigate the expressions used in Korean dance on th basis of its principle of forces. Korean dance has evolved into various creative forms, and basic analytical studies of these diverse forms and related breathing methods re required in the future.

Distribution of Anchovy School Catched by the Lift Net and Environmental factors in the Kamak Bay 2. Relation between Distribution of Anchovy school and Chlorophyll-a (가막만에서의 멸치 들망 어장의 분포.이동과 환경 요인과의 관계 2. 기초생산자의 출현과 어군의 분포)

  • 서영준
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.35 no.4
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    • pp.377-385
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    • 1999
  • In order to investigate the properties in distribution and movement of anchovy school catches by the lift net in the Kamak bay and their relation to the environmental factors, I. e., the amount of chlorophyll-a and turbidity were observed from June to August in 1997 and compared with the catch of anchovy by the lift net. The results obtained are summarized as follows;1) The amount of chlorophyll-a ranged from 4.0 to 12.0 mg/$m^3$ on July and from 3.0 to 15.0 mg/$m^3$ on August in horizontal distribution, the amount of chlorophyll-a ranged from 3.0 to 8.0mg/$m^3$ on June, from 5.5 to 11.6 mg/㎥ on July, and from 6.0 to 11.1 mg/$m^3$ on July and from 1.0 to 6.0ppm on August, respectively. 2) Anchovy school can be presurmed, they are come from north of bay, visited and distributed through east of bay at the middle of June. Moreover, they spreaded in all bay. Then gradually, when July arrive, they go to the south the nearest the coasts, and they are outflow through the south entrance of bay at the end of August.3) The catch of anchovy was highest on July, poor second on August, and lowest on June. The chlorophyll-a and the turbidity influenced remarkably on the distribution and movement of anchovy school and the influence of chlorophyll-a was alrgest.

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Cortical Granule Distribution During In Vitro Maturation and Fertilization of Porcine Oocytes (돼지난자의 체외성숙 및 수정시 일어나는 표층과립막세포의 분포변화에 관한 연구)

  • 송상진;권중균;도정태;김남형;이훈택;정길생
    • Korean Journal of Animal Reproduction
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    • v.20 no.3
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    • pp.343-351
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    • 1996
  • The objectives of this study are to determine cortical granule distribution during in vitro maturation, parthenogenetic activation and in vitro fertilization of oocytes, and to investigate effects of microfilament inhibitor on the cortical granule distribution during in vitro maturation and fertilization of oocytes in the pig, The corti-cal granule distribution were imaged with fluor-escent labeled lectin under laser scanning confocal microscope or detected by transmission electron microscope. At germinal vesicle stage, cortical granule organelles were located around the cell cortex and were present as a relatively thick area on the oolema. Microfilaments were also observed in a thick uniform area around the cell cortex. Following germinal vesicle break down,microfilaments concentrated to the condensed chromatin and cortical granules were observed in the cortex. Treatment with cytochalasin B inhibited microfilament polymerization and prevented movement of cortical granules to the cortex. Cortical granule exudate following sperm penetration was evenly distributed in the entire perivitelline space. Therefore, these results suggested that the microfilament assembly is involved in the distribution, movement and exocytosis of cortical granules during maturation and fertilization of porcine oocytes. (Key words cortical granule, porcine, maturation, fertilization).

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Automatic Detection of Rapid Eye Movement Distribution in Narcoleptic and Normal Sleep Using Fuzzy Logic (퍼지 추론을 이용한 REM의 자동 검출 : 기면증과 정상수면의 REM 분포 연구)

  • Park, H.J.;Han, J.M.;Choi, M.H.;Jeong, D.U.;Park, K.S.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.201-202
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    • 1998
  • In this paper we suggested an automated method for detecting and counting rapid eye movement(REM) using EOG during sleep. This method is formulated by two step fuzzy logic. At first step, the velocity and the distance of single channel eye movement are used for the fuzzy input to get the possibility of being REM at each EOG. At second step, the two possibility values of both EOG from the first step and the correlation coefficient of both eye movements are used for the fuzzy logic input, and the output is the final possibility of being Rapid Eye Movement. We applied this algorithm to the normal and narcoleptic sleep data and compared the difference. We found the possibility that the count of REM can be a parameter that has significant physiological meanings.

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A Numerical Study of an Effect of the Aspect Ratio on Smoke Movement in funnel Fires (터널 화재시 종횡비에 따른 연기 거동에 관한 수치해석적 연구)

  • 이성룡;김충익;유홍선
    • Fire Science and Engineering
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    • v.18 no.2
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    • pp.1-6
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    • 2004
  • In this study, numerical simulations were conducted to analyze an effect of the aspect ratio on smoke movement in tunnel fires using FDS 3.0. It was confirmed an application for tunnel fires in comparison with experimental results. The results showed relatively good agreement with experimental data within 1$0^{\circ}C$. Clear height of CFD by velocity distribution was about 3% higher than that of experiment. Smoke movement was confirmed by the analysis of temperature and velocity field. Results from variation of the aspect ratio showed good agreement with experimental data. The temperature at the vicinity of the fire source became lowly with the increase of the aspect ratio. But, decrease rate of the temperature was reduced by the decrease of the heat loss to the width direction.

Design of small slotless BLDC motor for robot using Space Harmonic Analysis Method (공간 고조파 해석 기법을 이용한 로봇용 소형 Slotless BLDC Motor 설계)

  • Kim, Hong-Seok;Kim, Sung-Jin;Kang, Gyu-Hong
    • Proceedings of the KIEE Conference
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    • 2005.07b
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    • pp.1132-1134
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    • 2005
  • This paper presents a design strategy of Slotless type BLDC motor using the space harmonic field method. The distribution of Back emf and torque are considered by movement of the Permanent Magnet and armature current. The result of magnetic field distribution, back-emf, and torque are in agreement with FEM.

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A Study on the Use Scope of Lifetime Sports Facilities (생활체육시설 이용권에 관한 연구)

  • Min, Young-Gi
    • Journal of The Korean Digital Architecture Interior Association
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    • v.7 no.2
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    • pp.73-78
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    • 2007
  • Proper methods for facilities distribution are suggested by the examination of researches on facilities distribution, the analysis of the scope that facilities are used, and the consideration of facilities demand, and proper distribution and placement of facilities suitable for each stage is suggested. The theoretical examination for proper distribution and the analysis of the use scope is made. As a result. the area covers four dongs(administrative unit) within 1km. The $80{\sim}90%$ of residents who use the existing facilities are the ones living within 1km and so the zone of life in everyday life depending on walking as a means of movement is found to be expanded by the developments in transportation means and road construction. Therefore I suggested that lifetime sports facilities be established within the use scope whose radius and area are 1km and 4km2, respectively, regarding the sports facilities as a community center which can playa role of an institution of community center.

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Analyses on Solute Transport with the Movement of an LNAPL on the Water Table (지하수면 위의 LNAPL 이동을 고려한 용질이동에 대한 분석)

  • 김지훈;최종근
    • Journal of Soil and Groundwater Environment
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    • v.8 no.3
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    • pp.1-7
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    • 2003
  • A modified model was developed for solute transport in porous media that can consider the movement of an LNAPL above the water table. From the results of sensitivity analyses with and without considering LNAPL movement, there are some differences according to the hydraulic gradient, the quantity of oil leakage and dispersivity. The mean deviation between the model in this study and a conventional model without LNAPL movement increases as the hydraulic gradient decreases and the quantity of oil leakage increases. Variation of dispersivity has no influence on the magnitude of the mean deviation. However, the spatial distribution of the deviation between the two models is wider as dispersivity increases. Furthermore, groundwater is at high risk of contamination in the vertical direction in the case that transverse dispersion value is large. A conventional model underestimates the concentration of solute in an aquifer where the movement of an LNAPL cannot be negligible: Based on the study results, it is important to understand how fast the LNAPL moves on the water table for realistic prediction of solute transport in an aquifer with the movable LNAPL on the water table.