• 제목/요약/키워드: pressure pattern

검색결과 1,546건 처리시간 0.034초

해저면에 설치된 2차원 복합해저관로 주위의 유동특성에 관한 실험적 연구 (A Study of Flow Pattern around the Two-Dimensional Dual Subsea Pipeline on Sea Bottom)

  • 나인삼;조철희;정우철;김두홍
    • 한국해양공학회:학술대회논문집
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    • 한국해양공학회 2001년도 추계학술대회 논문집
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    • pp.122-127
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    • 2001
  • As pipelines are often used to transport gas, oil, water and oil products, there are more than one pipeline installed in the offshore field. The size and space of pipelines are various depending on the design specifications. The pipelines are to be designed and installed to secure the stability to external loads during the installation and operation period. The flow patterns are very complex around the pipelines being dependent on incoming flow velocity, pipelines size and space. To investigate the flow patterns, number of experiment are conducted with visualization equipment in a circulating water channel. The flow motion and trajectory were recorded from the laser reflected particles by camera. From the experiment the flow patterns around spaced pipelines were obtained. Also pressure gradient was measured by mano-meter to estimate the hydrodynamic forces on the behind pipeline. The results show that the various sizes and spaces can be affected in the estimation of external load. The complex flow patterns and pressure gradients can be effectively used in the understanding of flow motion and pressure gradient.

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Gait Motion Capture 및 족압 측정을 이용한 보행특성시험 및 동력학적 인체 시뮬레이션 연구 : 한국인 성인 남자의 군장착용 보행 특성 해석 (A Study on the Gait Test Human Dynamic Simulation Using Gait Motion Capture and Foot Pressure Measurement : Analysis of Gait Pattern with Wearing Military Equipment of Korean Male Adult)

  • 이세훈;이영신;최영진;이장원;채제욱;최의중;김인우
    • 한국정밀공학회:학술대회논문집
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    • 한국정밀공학회 2005년도 춘계학술대회 논문집
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    • pp.877-880
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    • 2005
  • This paper suggests gait analysis and gait simulation method using Gait Motion Capture equipment and plantar pressure measurement system. The gait of normal person and how it will be effected by added weight with wearing military equipments are studied by suggested method. It is measured that a change of gait pattern when wears military equipments with Korean male adult(height 180 cm, weight 70 kg) and simulated its results.

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로켓노즐에서 발생하는 횡력변동에 관한 연구 (Study on the Lateral Force Fluctuations in a Rocket Nozzle)

  • ;이종성;김희동
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2009년도 춘계학술대회 논문집
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    • pp.315-319
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    • 2009
  • Investigation of the lateral force fluctuations in an axisymmetric overexpanded compressed truncated perfect (CTP) nozzle for the shutdown transient is presented. These nozzles experience side-loads during start-up and shut-down operations, because of the flow separation at nozzle walls. Two types of flow separations such as free shock separation (FSS) and restricted shock separation (RSS) shock structure occur. A two-dimensional unsteady numerical simulation has been carried out over an axisymmetric CTP nozzle to simulate the lateral force fluctuations in nozzle during shutdown process. Reynolds Averaged Navier-Stokes equations are numerically solved using a fully implicit finite volume scheme. Governing equations are solved by coupled implicit scheme. Two equation k-$\omega$ SST turbulence model is selected. Unsteady pressure is measured at four locations along the nozzle wall. Present pressure variation compared well with the experimental data. During shutdown transient, separation pattern varies from FSS to RSS and finally returns to FSS. Several pressure peaks are observed during the RSS separation pattern. These pressure peaks generate lateral force or side loads in rocket nozzle.

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비스트레치 소재와 스트레치 소재를 이용한 중년여성 재킷 착의적합성 연구 (A Study on Wearing Fitness of Middle Aged Women's Jacket with Non-Stretchable Fabric and Stretchable Fabric)

  • 박지은;김희은
    • 한국의류산업학회지
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    • 제6권4호
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    • pp.485-491
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    • 2004
  • The purpose of this study is to analyze the wearing fitness of middle aged women's jacket with non-Stretchable Fabric and stretchable fabric. We surveyed the size of jackets and process of pattern making with stretchable fabric in companies which produce the clothing mainly for middle aged women. Based upon the result of process of pattern making, two kind of experimental jacket with non-stretchable and stretchable fabric were made. We measured space length between body and garment using 3D scanner and analyzed the clothing pressure 7 parts of body with 3 kinds of arm raising. The result were as follows : 1. Most parts of space length except bust were higher in non-stretchable jacket than in stretchable jacket. 2. Clothing pressure showed greater value with non-stretchable fabric jacket than with stretchable fabric jacket. Clothing pressure in upper arm point areas increased as the angle of the arm raising increased. Therefore, the sleeve width and armhole depth should he considered when the amount of wearing ease were reduced in jacket with stretchable fabric.

2중판 오리피스를 이용한 기액 2상유량계의 개발 (Development of a 9as-liquid two-phase flowmeter using double orifice plates)

  • 이상천;이상무;남상철
    • 설비공학논문집
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    • 제10권5호
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    • pp.619-629
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    • 1998
  • An experimental work was conducted to investigate a feasibility of simultaneous measurement of gas-liquid two-phase flowrates with double orifice plates using air and water. The tests were carried out under the atmospheric pressure and at the ambient temperature using two different tube sizes. Qualities of an air-water flow in the present study have values less than 0.1 and thus the mixed flow showed bubbly, plug, slug flow regimes. The probability density function (PDF) and the power spectral density function (PSDF) of the instantaneous pressure drop traces for the flow regimes were obtained. It is found that some distinctive features exist in the distribution of these functions, depending upon the two-phase flow pattern. The time-averaged value of the instantaneous pressure drop increases with increasing gas and liquid flowrates, showing a single-valued function for the total mass flowrate and the quality. It is also found that the two-phase discharge coefficient exhibits a consistent trend for variation of dimensionless parameters such as the superficial velocity ratio and the gas Reynolds number. The results indicate that simultaneous measurement of two-phase flowrate may be possible based upon a statistical analysis of the instantaneous pressure drop curves monitored using double orifice plates.

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퍼지 패턴인식법을 이용한 발전소 과도상태 판별 (Discrimination of Plant Transient by Using the Fuzzy Pattern Recognition)

  • 김종석;이동주
    • 한국공작기계학회논문집
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    • 제14권1호
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    • pp.37-43
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    • 2005
  • Plant pipe has a fatigue life which is induced by repeated stress come from the variation of temperature and pressure. To avoid the fatigue crack of plant pipe which is produced by long term repeated stress, plant operator has to limit the mont of operating transient. This paper introduced the study result about discrimination methodology of plant transient by using the fuzzy pattern recognition. As result of applying the fuzzy pattern recognition to actual plant operation data, it is confirmed that fuzzy pattern recognition methodology can be useful for the comparison of similarity for the transients of similar output but has different time pattern.

자동차 타이어 패턴 소음 예측에 따른 차량 Road Noise 실험적 평가 (An Experimental Evaluation for Vehicle Road Noise on the Pattern Noise Prediction)

  • 왕성준;이근수;김인동
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 춘계학술대회 논문집
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    • pp.361-364
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    • 2011
  • In this paper, This work demonstrates a experimental evaluation for vehicle road noise NVH performance from the component-level NVH measurements of Tire. The power unit noise from tire emitted by cars has been reduced. It has been found that tire noise dominates noise produced by the power train when vehicles are driven at high constant speed. Therefore tire pattern noise is affected by pattern and vehicle and transmission loss. Tire noise mechanism is generated by several mechanisms. The sound of tire can propagate either through the air or through the structure of vehicle. Pattern noise is the result of pressure variations through the air to the interior side of vehicle. Especially, smooth asphalt, the periodicity of tread design, groove depth is important factor, which have an influence on the reduction of tire pattern noise.

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3D Pattern Construction and Its Application to Tight-fitting Garments for Comfortable Pressure Sensation

  • Jeong Yeon-Hee;Hong Kyung-Hi;Kim See-Jo
    • Fibers and Polymers
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    • 제7권2호
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    • pp.195-202
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    • 2006
  • Tight-fitting clothing pattern reflecting the accurate information of the 3D body shape has been one of the challenges for garment industry, however, fitting problems still exist. The objectives of the paper is to develop a 2D pattern which fits tightly to the 3D human scan data for sports suits that need comfort and function for maximum performance. In this study, the user graphic interface application software for the semi-automatic garment pattern generation has been implemented using the triangle simplification scheme together with 2D projections of free-falling of 3D surface polygons keeping the original 3D surface area preservation. A typical application of the developed pattern to the functional body suits is presented and verification of the proposed method is also provided.

고혈압 단계별 변증특성 분석 (Pattern Analysis in Patients with Hypertension grades)

  • 양창섭;김영은;김창석;김철;송미영
    • 동의생리병리학회지
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    • 제26권6호
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    • pp.934-939
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    • 2012
  • To investigate and characterize basic patterns of prehypertension. Participants were divided into three groups; ideal blood pressure(n=40), prehypertension(n=62), and stage 1 hypertension groups(n=68) according to the JNC 7 standards. They answered questionnaire asking various symptoms and received clinical examination. Data were collected and analyzed in the focus of three Zheng patterns, cold-heat, deficiency-excess and four major hypertension types. Analysis of variance was used to find differences among groups. In addition, relationship between the cold-heat trends and risk factors of hypertension were analyzed using Pearson's correlation analysis. Three risk factors; age, body mass index (BMI), and fasting blood sugar (FBS) showed intergroup differences. Statistical significances were revealed in the cold-heat pattern and two hypertension subtypes. The cold scores decreased from $4.8{\pm}1.84$ to $3.9{\pm}1.88$ and $3.7{\pm}1.27$ (p=0.022), while the heat increased from $1.9{\pm}1.32$ to $2.8{\pm}1.72$ and $2.8{\pm}1.48$ (p=0.009). Additionally two hypertension subtypes, the excessive liver fire, and the yin-yang deficiency showed significant differences. Cold had negative correlations with blood pressure (both systolic and diastolic), BMI, triglyceride, and FBS. Heat had positive correlations with systolic blood pressure, BMI, triglyceride, and FBS. Prehypertension could be characterized by using the cold-heat patterns. The cold-heat are correlated with Blood pressure, BMI, blood lipids and sugar.

외부흐름 중공사 막형 인공폐의 액체흐름과 압력손실 (Liquid Flow and Pressure Drop of an Outside Flow Membrane Oxygenator with Hollow Fibers)

  • 이삼철;김기범
    • 대한의용생체공학회:의공학회지
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    • 제23권1호
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    • pp.27-32
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    • 2002
  • 본 연구에서는 혈관내 혈액 흐름의 압력손실을 최소화하여야 하는 제한 인자를 만족하는 새로운 막형 인공폐에서 액체흐름경향과 중공사 개수에 대한 압력손실 영향을 고찰하고자 하였다 막형 인공폐는 380 $\mu m$의 중공사 외경과 600 mm의 축 방향 길이를 갖는 수 백 개의 중공사로 이루어진 다발이다 중공사 다발은 8가지로 변화시켰으며 흐름은 펌프를 이용하여 조절하였다 혈액대용물질로 글리세롤 용액과 물을 사용하여 압력손실을 측정하였으며 동일한 흐름 경향을 각 중공사들에서 얻었다. 700개의 중공사로 이루어진 막형 인공 폐의 외부 압력손실은 13-16 mmHg이었으며 중공사 개수의 감소에 따른 마찰계수는 중공사와 액체와의 효과적인 접촉이 일어나므로 증가되었다.