• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.735-738
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• 1997

The aerodynamic charateristics of high speed train can be improved by fore-body design. In this paper, the design a fore-body shape which has optimal aerodynamic charateristics, 6 models of fore-body shape are proposed and the change of aerodynamic characteristics is studied through calculations of flow field around high speed train fro each fore-body shape. The flow field around high speed trains are calculated using Navier-Stokes equation. The variational trends of aerodynamic characteristics are studied from the result of flow calculation around high speed trains for 6 fore-body shapes.

• 한국전산유체공학회지
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• 제1권1호
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• pp.81-87
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• 1996

The aerodynamic charateristics of high speed train can be improved by well-designing of its fore-body shape. In this paper, as a way of the design a fore-body shape which has optimal aerodynamic charasteristics, 9 models of fore-body shapes are proposed and the change of aerodynamic charateristics is studied through calculations of flow field around high speed train for each fore-body shape. The flow field around high speed trains are calculated using Thin-Layer Navier-Stokes equation and Chimera grid technique. The application of Chimera grid technique to these flow calculations over high speed train which has ground plane under the train makes grid generation easily. As a computaional algorithm, Pulliam and Chaussee's Diagonal algorithm, the modified form of the Beam and Warming's AF scheme which operates on block-tridiagonal matrices, is selected to reduce computaional time. Introducing hole points flag concept to this Diagonal algorithm. a algorithm for Chimera grid is generated. The variational trends of aerodynamic characteristics are studied from the results of flow calculations around high speed trains for 9 fore-body shapes.

• 대한조선학회논문집
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• 제55권3호
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• pp.252-264
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• 2018

The calculation of steady-state cavitating flows around Supercavitating Underwater Bodies (SUB's), which consist of a circular disk head (cavitator), a conical fore-body, a cylindrical middle-body and either a boat-tail or a flare-tail, are carried out. To calculate the axisymmetric cavitating flow, used is a commercial computational fluid dynamics code based on the finite volume method, Fluent. From the analysis of numerical results, the cavity and drag, affected by the fore-body and tail of the SUB's, are investigated. Firstly, the effect of the fore-body shape is investigated with the same disk cavitator and a cylindrical rear-body of fixed diameter. Then with the same cavitator and a fixed fore-body, the effect of the rear-body shape is investigated. Before the cavity generated by the cavitator covers the slant of fore-bodies sufficiently, the larger the cone angle of the fore-body(i.e., the shorter the slant length), the larger the drag and the slower the development of cavity. After the cavity covers the fore-body completely so that the pressure drag component of the body is vanished, the characteristics of drag-velocity curves are identical. Also, as the tail angle is bigger, the cavity generated by the cavitator is suppressed further and the drag becomes larger. The peak of the drag appears for the flare-tail, i.e., when the tail angle is positive(+). On the contrary, the trough of the drag appears for the boat-tail, i.e., when the tail angle is negative(-). When the tail angle is 5 degrees, the peak of the drag appears at the body speed of 80m/s and the value of the drag is 43% larger than that at the design speed of 100m/s. When the tail angle is -5 degrees, the trough of the total drag appears at 75m/s and that drag is 30% smaller than that of the cavitator, which means the rest of the body has a negative drag.

• 한국의류산업학회지
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• 제20권2호
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• pp.219-225
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• 2018

The purpose of this study is to make an ideal dummy for adult Maltese with proper investigation of its character and direct measurement of dog body-shape. The results of the study are as follows; First, there were 6 factors to affect the characteristics of Maltese body in the analysis, which are size of body, leg shape, chest shape, leg thickness, body length, length between fore-legs. In the cluster analysis with the 6 factors there were two types of Maltese body. Type 1 has body characteristics with large body, thick leg, and small distance between front legs. Type 2 has average size of all factors including body size, leg thickness, and length between fore-legs. Second, type 2 was selected as a representative one to make a dummy reflected body shape of characteristics because it took 67.71% from entire considered factors and has average value in the measured size. The first dummy pattern was planned by copying the surface area of the representative body shape with the method of surgical tape. A dummy of single body with trunk and legs was made using 30's cotton cloth, polyester inside batting, compressed form PVC and metallic wire on the joint of trunk and legs to support dummy shape. The second pattern was made by correcting size difference of the pattern and adding the pattern of neck covering plate, metal magnetic button was inserted on the center of joint area of trunk and legs to make detachable legs for easy slip on and off the pet's wear.

• 대한조선학회지
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• 제26권2호
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• pp.1-12
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• 1989

본 논문에서는 선체로부터 멀리 전파해 나아가는 선형파와 선체 가까이에 존재하는 쇄파로 인한 조파저항성분을 최소화시키는 방법을 보여준다. 본 방법은 선형조파저항의 최적화 방법과 시험자료 분석을 통한 쇄파저항의 통계적 최적화방법으로 구성된다. 응용목적으로서, 수선형상이 포물선이고 측면이 수직한 모형을 기본선형으로 택하였고, 선형파를 최적화하는 방법과 경험적인 방법을 통하여서 선체전반부의 횡단면적 곡선을 변화시킨 두척의 수정모형선을 얻었다. 3척의 선형에 대한 시험 및 분석결과로부터 선체전반부의 횡단면적 곡선의 변화에 따른 선형파저항과 쇄파저항과의 상관관계를 살펴보았다. 본 방법으로 선체전반부가 최적화된 선형은 설계속도($F_n=0.26$)에서 기본선형에 비하여 약 47%의 조파저항감소를 보이고 있다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.856-867
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• 2020

This paper aims to provide the most useful method of determining an optimum LCB position and design direction of fore- and aft-body hull shape for a SLBV. It is known that the SLBV has a lower length-to-beam ratio, larger Cb and simpler stern shape designed for the installation of azimuth thrusters comparing to those of conventional LNG carriers. Due to these specific particulars of SLBV, the optimum LCB position was very different to that of conventional LNG carrier. And various approaches were applied to determine the optimum fore- and aft-body hull shape. The design direction for the optimum hull-form was evaluated as the minimization of the total resistance which includes the wave-making resistance and form-drag with numerical simulation.

• 대한조선학회논문집
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• 제56권4호
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• pp.327-334
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• 2019

Recently, there has been a growing interest in artificial supercavitation as a way to reduce friction drag of submerged vehicles. A cavitator plays an important role to generate the supercavity, so many studies have focused on the case of cavitator only. However, the body shape behind the cavitator affects the growth of the supercavity and this effect must be considered for evaluating the overall performance of the system. In this work, we conducted experimental investigation on artificial supercavitation generated by different combinations of the cavitator and body. We observed the supercavity pattern by using a high-speed camera and measured the pressure inside the cavity by using an absolute pressure transducer. We estimated the relation between the amount of injected air and the supercavity shape for different combinations. In summary, the disk type cavitator generates larger supercavity than that of the cone and ellipsoidal cavitators, but cavity development speed is relatively slower rather than the others. Furthermore, fore body angle plays an important role to generate the supercavity enveloping the entire body.

• 한국정보과학회논문지:소프트웨어및응용
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• 제36권12호
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• pp.996-1008
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• 2009

본 논문은 뼈대-구조(skeleton) 형태의 Active Shape Models을 이용한 사람의 자세 정합에 대한 새로운 접근 방법을 제안한다. 제안된 방법은 모델 생성과 정합 과정에서의 빠른 수행 시간을 위해 기존 윤곽 형태(silhouette)의 모델이 아닌 뼈대-구조 형태의 모델을 적용하였다. 기존 Active Shape Models을 뼈대-구조 형태로 사람 자세 정합에 적용했을 경우 자세를 결정짓는 팔과 다리의 부정확한 정합은 사람 몸의 다양한 색상 정보와 전후(fore-rear direction)만을 고려한 특징점(landmark)의 방향정보로 인해 발생되며, 이러한 문제점은 입력 영상의 차영상 정보와 사람의 자세를 결정짓는 팔과 다리의 중요 특징점에 방향정보를 추가하여 해결하였다. 사람의 뼈대-구조 모델을 생성하기 위해 600개의 이미지를 사용 하였으며, 생성된 형태 모델은 사람의 자세에 정합될 수 있는 17개의 특징점을 포함한다. 정합 과정에서 최대 30번 이하의 반복 과정을 수행 하며, 최대 수행 시간은 0.03초로 빠른 수행 시간의 결과를 얻었다.

• 대한조선학회논문집
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• 제31권2호
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• pp.78-85
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• 1994

물체가 입수시 두부에 큰 충격을 받게 되며 이 충격량은 진입하는 물체의 두부형상이나 입사각에 따라서 많은 차이를 보인다. 본 논문에서는 선수부가 평면 부분을 포함하는 형상을 갖는 물체가 임의 각도 입수시의 충격량을 계산하였다. 선수부가 납작한 부분을 포함하면 임의 각도 입수시 물체의 접수부분이 기하학적으로 복잡해진다. 3차원 물체를 여러 영역으로 분할하여 각 부분을 겹3차 B-spline으로 표시하여 곡면을 정확히 나타낼 수 있도록 하였다. 자유표면 조건은 $\phi=0$을 적용하였으며, 경계치 문제는 Green함수를 이용하여 해석하였다.

• 복식문화연구
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• 제8권5호
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• pp.668-680
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• 2000

The study presents the general types and individual differences of the shape of the adult women's neck and shoulder in our country. It is based on the average value, the standard deviation, the maximum value, the standard deviation, the maximum value, the minimum value and c.v. measured from the women at the age of 19 through 64. The results of this study are as follows ; 1. The factors by factor analysis are five. The first is the size factors of the neck and shoulder. The second is shape factor of neck. The third is plane view and length factor of the neck. The fourth is the side view factor of the neck and shoulder. The fifth is the shape factor of shoulder. Therefore the shape of the neck and shoulder should be examined in the shape factors as well as in the size factors as well as in the size factors for the designing body-suitable clothes. 2. The factors of the concrete objects are the solid view of neck and shoulder, the cross-sectional view of neck line, side view of neck and shoulder and length of neck. The explainable measuring items for the factors are the difference of the length between lower neck round line and the 4㎝ above neck round line, the length of neck, the angle of inclination between fore neck and back neck, the angle of inclination of the side shoulder, the difference of the height between fore neck point and back neck point, the width of shoulder, the width of chest and the width of back. 3. The concrete objects of the neck and shoulder have five types ; Type Ⅰ is average type, Type Ⅱ is thick short neck and the drooping shoulder type, Type Ⅲ I is slender long neck and lean-back shoulder type, Type Ⅳ is thick and rising shoulder type and Type Ⅴ is slender and drooping shoulder type.