• Title/Summary/Keyword: Appendage

Search Result 167, Processing Time 0.033 seconds

A Study on Hydrodynamic Force Characteristics of Manta-type Unmanned Undersea Vehicle with the Parameter of Appendage Shape (Manta형 무인잠수정의 부가물 형상에 따른 동유체력 특성에 관한 연구)

  • Bae, Jun-Young;Sohn, Kyoung-Ho
    • Journal of Navigation and Port Research
    • /
    • v.33 no.5
    • /
    • pp.309-314
    • /
    • 2009
  • The influence of different appendage shape on the characteristics of hydrodynamic forces on Manta-type Unmanned Undersea Test Vehicle(MUUTV) was discussed experimentally. Fuselage only MUUTV model and two types of MUUTV model with different appendage geometries were considered as the subject of discussion Oblique tow experiment was carried out in circulating water channel with three MUUTV models. A point of difference in hydrodynamic force characteristics among three models was indicated. Furthermore, the linear hydrodynamic derivatives obtained from model experiment were compared with theoretical calculation results from slender body theory, added mass theory and etc. Based on the hydrodynamic force characteristics, motion stability of two types of MUUTV model with different appendage geometries was compared each other. Through the above analysis, the more suitable shape of appendage geometry was made clear.

A Study on Hydrodynamic Force Characteristics of Manta-type Unmanned Undersea Vehicle with the Parameter of Appendage Shape (Manta형 무인잠수정의 부가물 형상에 따른 동유체력 특성에 관한 연구)

  • Bae, Jun-Young;Sohn, Kyoung-Ho
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
    • /
    • 2009.06a
    • /
    • pp.5-6
    • /
    • 2009
  • The influence of different appendage shape on the characteristics of hydrodynamic forces on Manta-Type Unmanned Undersea Test Vehicle(MUUTV) was discussed experimentally. Fuselage only MUUTV model and two types of MUUTV model with different appendage geometries were considered as subject of discussion Oblique tow experiment was carried out in circulating water channel with three MUUTV models. A point of difference in hydrodynamic force characteristics among three models was compared and discussed. Furthermore, the linear hydrodynamic derivatives obtained from model experiment were compared with theoretical calculation results from slender body theory, added mass theory and ete. Based on the hydrodynamic force characteristics, motion stability of two types of MUUTV model with different appendage geometries was discussed and compared each other. Through the above analysis, the more suitable shape of appendage geometry was made clear.

  • PDF

The Effect on Appendage muscle strength due to Increase in Occlusal Vertical Dimension (수직적 교합고경의 증가가 사지 근력에 미치는 영향에 관한 연구)

  • An, Su-Jin;Lee, Sung-Bok
    • Journal of Dental Rehabilitation and Applied Science
    • /
    • v.17 no.4
    • /
    • pp.231-244
    • /
    • 2001
  • This study was conducted to observe the effect on appendage muscle strength according to increase in occlusal vertical dimension. For this study, ten males with a mean age of 21 were selected. The subjects had a complete or almost complete set of natural teeth and reported no subjected symptoms of pain or dysfunction in the masticatory system. The tested occlusal splints were made at the position of increased occlusal vertical dimension of 2mm, 3.5mm, and 5mm from the ICP. Before and after wearing occlusal splints, the appendage muscle strength were tested by CybexII Dynamometer in each subject. The results were as follows : 1. When occlusal vertical dimension was increased, most of mean muscular strength values were increased except for those of supination and pronation of forearm at the position of 5mm increased occlusal vertical dimension. 2. The statistical analyses demonstrated that the increased occlusal vertical dimension position to be significantly stronger than intercuspal position for the muscle strength of the flexion and extension of hip, supination of forearm, external and internal rotation of knee, dorsiflexion and plantarflexion of ankle (p<0.05). 3. At the position of 3.5mm increased vertical dimension displayed the highest mean muscluar strength value than other positions. 4. Statistically demonstrated values, except for supination of forearm, internal rotation of shoulder, were related to lower appendage. Therefore splint was more effective on lower appendage than upper appendage to make muscle strength increased. 5. The mean increased rate of muscular strength tested on knee(57%), ankle(42%), and wrist(20%) were higher than hip(31%), elbow(14%), and shoulder(17%).

  • PDF

An experimental study on the improvement of resistance performance by appendage for 50 knots class planing hull form (50노트급 활주형선의 저항성능 개선을 위한 부가물 부착에 관한 실험적 연구)

  • Lee, Kwi-Joo;Park, Na-Ra;Lee, Eun-Jung
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.41 no.3
    • /
    • pp.222-226
    • /
    • 2005
  • A series of model tests carried out at the CWC of WJFEL for the purpose of prediction of resistance for the performance and improvement of resistance by attaching appendage for the ship of 50 knots class planing hull. The resistance performance evaluation has been carried out for the bare hull and for the appendage hull with two different depth of vertical type wedges. In the bare model test, trim and sinkage is calculated for the planing hull and the resistance is calculated. For minimizing the resistance, wedge appendage is attached and tested. Analysis and tests shows that for a 12.5mm wedge, resistance is minimum and overall power tallied to 5636ps.

Effects of the Fillet Forms on the Juncture Flow (Fillet 형상이 접합부 주위의 유동에 미치는 영향)

  • Kim, Sun-Young
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.34 no.1
    • /
    • pp.24-40
    • /
    • 1997
  • Horseshoe vortices generated around the juncture between the ship and her appendages often lower a performance of the ship by increasing the appendage drag and making a non-uniform wake on the propeller plane. This paper investigates numerically how the fillet around the juncture of the leading edge influences the juncture flow and the appendage drag. Computation has been made by solving Navier-Stokes equations with MAC method and the flows are at the Reynolds number of 5,000. Five fillets with different height-breath ratios and curvatures are chosen as test models to find out the effects of the shape of fillets on the appendage drag and wake. Computational results show that fillets with a smaller height-breath ratio and/or with a concave curvature has smaller appendage drag and more uniform wake.

  • PDF

Left Juxtaposition of Atrial Appendage Accompanying Complete TGA and Total Anomalous Pulmonary Venous Drainage (One Case Report) (와전 대혈관전위증과 전 페정맥 이상환류증을 동반한 양측심이의 좌측병치증 -1례 보고-)

  • 박재길
    • Journal of Chest Surgery
    • /
    • v.13 no.4
    • /
    • pp.448-454
    • /
    • 1980
  • The juxtaposition of atrial appendage may possibly be diagnosed by angiography recently, and it is widely regarded as an ominous sign of severe cyanotic congenital heart disease. However, it is apparently rare congenital cardiac anomaly in which the atrial appendages lie side by side, both to the left or right of the great arteries, known as left or right juxtaposition of the atrial appendages. Juxtaposition of the atrial appendages has no functional significance, since it does not, itself, cause any hemodynamic disturbance. But it`s presence always indicates the coexistence of other major cardiac anomalies. In review of literatures TGA and VSD are invariable present, and ASD is common. Other anomalies, such as, tricuspid atresia, pulmonary outflow that, obstruction bicuspid pulmonic valve, persistent SVC etc. are relatively high incidence. In this report, we present one case of 6 year old female child having left juxtaposition of atrial appendage combined with TGA [D-looping, D-transposition], TAPVD, large ASD, small VSD, and vertical vein.

  • PDF

A Study on the Development of Sea-Keeping Performance Improving Device for High Speed Fishing Vessel (고속어선의 운동성능 개선장치 개발에 관한 연구)

  • Lee, Kwi-Joo;Kim, Kyoung-Hwa;Park, Na-Ra
    • Journal of the Korean Society of Fisheries and Ocean Technology
    • /
    • v.41 no.1
    • /
    • pp.64-69
    • /
    • 2005
  • In spite of many efforts, in the design of high speed fishing vessel the sea-keeping performance improvement without neglection of resistance-propulsion performance by hull form itself has its limitations. In this paper, the development of sea-keeping improving appendage pitching and trim improver for high speed planing hull on behalf of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test and also has been proved the better resistance performance in the model test and full scale test.

Persistent Atrial Fibrillation Related to a Congenital Pericardial Defect and Left Atrial Appendage Herniation

  • Lee, Heemoon;Jeong, Dong Seop;Kim, In Sook;Park, Byung Jo
    • Journal of Chest Surgery
    • /
    • v.48 no.6
    • /
    • pp.429-431
    • /
    • 2015
  • Congenital pericardial defects (CPDs) are infrequent anomalies that are usually asymptomatic and are discovered incidentally during unrelated interventions. Here we report the case of a CPD with herniation of an enlarged left atrial appendage identified during total thoracoscopic ablation (TTA) for persistent atrial fibrillation (AF). The persistent AF was successfully treated with a hybrid procedure, in which TTA was followed by an electrophysiological study.

A Research on the Mathematical Modeling for the Estimation of Underwater Vehicle's Tail Plane Efficiency (수중함의 함미타 효율추정을 위한 수학모델링에 관한 연구)

  • Shin, Yong-Ku;Lim, Kyung-Sik;Lee, Seung-Keon
    • Journal of the Society of Naval Architects of Korea
    • /
    • v.42 no.3
    • /
    • pp.190-196
    • /
    • 2005
  • The ratio between the hydrodynamic force produced by a submarine tau appendage and that acting on an equivalent appendage in isolation is regarded as tail plane efficiency. It is an important parameter in numerical simulations because it has a significant effect on predicted stability, controllability, and maneuverability. The paper introduces some recent work to improve the reliability and general applicability of current methods of tail plane efficiency estimation.

A study on the development of resistance and pitching improving device for high speed fishing vessel (고속어선의 저항 및 핏칭 개선장치 개발에 관한 연구)

  • 이귀주;오훈택
    • Journal of Ocean Engineering and Technology
    • /
    • v.11 no.3
    • /
    • pp.89-94
    • /
    • 1997
  • In the design of high speed fishing vessel, its hull form has to be decided from a view point of resistance and propulsion performance without negelction of seakeeping characteristics. In spite of many efforts, the performance improvement by hull form itself has its limitations, specially for high speed craft. In this paper, the development of performance of resistance and seakeeping improving appendage for high speed planing hull on behalft of the hull form of fishing vessel has been introduced. The developed appendage verified its effectiveness in the full scale test.

  • PDF