http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
노기덕 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
A mechanism of hovering flight of small insects which is called the Weis-Fogh mechanism is applied to ship propulsion. A model of the propulsion mechanism is based on a two-dimensional model of the Weis-Fogh mechanism and consists of one or two wings in a square channel. A model ship equipped with thus propulsion mechanism was made, and working tests were performed in a sea. The model ship sailed very smoothly and the moving speed of the wing was small compared with the advancing speed of the ship.
노기덕 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
The performance enhancement for a propulsion mechanism of Weis-Fogh type was attempted by using the rubber wing. The elastic wings were made of rubber and wood with the rubber rate of 0%, 25%, 50% in the wing area. The thrust and drag on the wing were measured for the various velocity ratio V/U, the opening angles of α=15˚ and α=30˚ As the results the thrust increased, the drag decreased and the propulsive efficiency increased through entire velocity ratio V/U by using elastic wing.
展開板에 대한 數値解析 : 1. 展開板 주위에서의 유체흐름의 패턴 1. Pattern of Fluid Flow besides Otter Board
高冠瑞,權炳國,盧基德 國立統營水産專門大學 附設 水産科學硏究所 1990 수산과학연구소보고 Vol.2 No.-
平板型과 彎曲型展開板 주위에서의 流體特性을 파악하기 위하여 回流水槽에서 水素氣泡法에 의한 可視化實驗을 流速 0.05 및 0.1m/sec, 迎角 0˚~45˚까지 5˚ 간격으로 流線과 타임라인에 대해서 실시하였다. 1. 彎曲型展開板에서의 流線은 영각 20˚까지는 균일한 분포를 이루다가 영각 25˚에서 後面에 인접한 流線이 翼弦長의 1/3 지점에서 剝離가 시작되며 인접한 流線은 展開板의 후면쪽으로 휘어들어가고, 그리고 영각 35˚ 이상에서는 前緣에서 부터 剝離가 시작되면 迎角이 증가할수록 剝離層이 증가하는 것으로 나타났다. 2. 平板型展開板에서는 영각 20˚부터 前緣에서 渦와 剝離가 발생되며, 剝離層은 彎曲型과 마찬가지로 영각에 비례하는 것으로 나타났다. 3. 後緣에서 발생한 渦의 크기가 前緣의 것보다 약 2~3배 큰것으로 나타났다. 4. 展開板의 後緣에서 流線은 양 展開板 모두 展開板의 방향과 같은 방향으로 흐르다가 점차 유체흐름과 같은 방향이 되는 것으로 나타났다. 5. 展開板 前後面에서의 流速差는 영각 0˚~30˚에서 점차 증가하다가 영각 35˚이상에서는 그 차가 비슷하게 나타났다. 6. 영각 20˚~30˚에서 前後面의 流速差는 彎曲型의 경우 後面의 流速이 前面보다 약 1.4~1.5배 빠르게 나타났으며, 平板型은 약 1.2배 빠르게 나타났다. The authors carried out a visiualizational model test by the hydrogen bubble method to examine the pattern of the fluid flow besides the simple camber type and plane type otter board in circulation water channel. The experimental conditions are velocity of flow 0.05 and 0.1m/sec, angle of attack 0˚∼45˚(5˚step). The results obtained are as follows: 1. In the case of the simple camber type otter board located angle of attack 25˚, vortex at the leading edge was geneated at 1/2 of chord length. 2. Size of the vortex generated in the trailing edge was about 2∼3 times larger then that of the leading edge. 3. In the case of the simple camber type otter board located angle of attack 30˚, separation of stream-line at leading edge was generated at 1/3 of chord length. 4. In the case of the plane type otter board, separation of stream-line at leading edge was generated from angle of attack 20˚. 5. Nearest stream-line in the back side of the simple camber type otter board was bent in the direction of otter board when the angle of attack was 25˚ and 30˚, and in the case of plane type otter board was expanded outside of the flow direction. 6. Area separated of the simple camber type otter board at the angle of attack 30˚ was smaller then that of plane type otter board. 7. Flow speed in the back side of the simple camber type otter board was about 1.4 times faster then that in the front side, and in the case of the plane otter board about 1.2 times faster.
Calculation of Thrust and Drag Characteristics for Ship′s Propulsion Mechanism of Weis-Fogh Type
Ro, Ki-Deok The Korean Society of Mechanical Engineers 2000 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.14 No.11
The flow field if a ship's propulsion mechanism of Weis-Fogh type is studied by the discrete vertex method. The wing in a channel is approximated by a finite number of bound vortices, and free vortices representing the separated flow are introduced from the trailing edge if the wing. The time histories of the thrust, the drag, and the moment acting on the wing are calculated, including the unsteady force due to the change of strength of the bound vortices. These calculated values agree well with the experimental values. The flow field of this propulsion mechanism is numerically clarified.
Flow Past Airfoil Moving Reciprocally in a Channel by Vortex Method
Ro Ki-Deok The Korean Society of Mechanical Engineers 2006 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.20 No.8
The velocity and pressure fields of a ship's propulsion mechanism of the Weis-Fogh type, in which a airfoil moves reciprocally in a channel, are studied in this paper using the advanced vortex method. The airfoil and the channel are approximated by a finite number of source and vortex panels, and the free vortices are introduced from the body surfaces. The viscous diffusion of fluid is represented using the core-spreading model to the discrete vortices. The velocity is calculated on the basis of the generalized Biot-Savart law and the pressure field is calculated from integrating the equation given by the instantaneous velocity and vorticity fields. Two-dimensional unsteady viscose flows of this propulsion mechanism are numerically clarified, and the calculated results agree well with the experimental ones.
Ro Ki-Deok,Kang Myeong-Hun,Kong Tae-Hee The Korean Society of Marine Engineering 2005 한국마린엔지니어링학회지 Vol.29 No.7
The velocity and pressure fields of a ship's Weis-Fogh type propulsion mechanism are studied in this paper using an advanced vortex method. The wing (NACA0010 airfoil) and channel are approximated by source and vortex panels. and free vortices are introduced away from the body surfaces. The viscous diffusion of fluid is represented using the core-spreading model to the discrete vortices. The velocity is calculated on the basis of the generalized Biot-Savart law and the pressure field is calculated from an integral, based on the instantaneous velocity and vorticity distributions in the flow field. Two-dimensional unsteady viscous flow calculations of this propulsion mechanism are shown. and the calculated results agree qualitatively with the measured thrust and drag due to un-modeled large fluctuations in the measured data.