• 제목/요약/키워드: Wind hole

검색결과 82건 처리시간 0.028초

프로펠러에 의한 LNG 운반선 이중모형 선미의 속도변화 계측 (Measurement of Velocity Field Change around Stern of LNG Carrier Double Body Model by Propeller)

  • 김병준;최순호;김형태;반석호
    • 대한조선학회논문집
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    • 제42권5호
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    • pp.448-457
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    • 2005
  • The experiment was performed at the large wind tunnel of the Chungnam National University to measure the velocity distribution around the stern of a Liquefied Natural Gas Carrier model. The data, mean velocity vectors of turbulent shear flows at the stern and near-wake including the propeller plane, were obtained by a five-hole Pilot tube for the double body model fixed inside the wind tunnel test section. The present result of the double body model shows a close agreement with the result of the lowing tank experiment performed by the KRISO for the same ship model. The characteristics of the LNG stern flow are discussed based on the measured velocity distribution. The data can be very useful for the validation of some numerical methods in computational fluid dynamics.

5공 프로브 실험실용 교정 시스템 개발 (Development of a Laboratory-based Calibration System for 5-Hole Probes)

  • 김창민;백승찬;지창은;황원태
    • 한국가시화정보학회지
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    • 제18권3호
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    • pp.122-128
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    • 2020
  • In the field of experimental fluid dynamics, the 5-hole probe is one of the most widely used tools to measure flow velocity and pressure. We hereby describe the development of an inexpensive laboratory-based flow calibration system for 5-hole probes. The system is applied to a custom L-shaped probe, and the probe performance is compared against a standard commercial probe in a custom wind tunnel. The setup allows rotation of the probe around the yaw and pitch axes. Static and total pressure values are calculated, and then calibration maps are constructed based on the yaw and pitch angles. Using these maps, errors of the custom probe are found to be ±5% for velocity magnitude and ±3° for direction, compared to the commercial probe, when both pitch and yaw angles are within 40°.

아토피 피부염의 주증상에 대한 문헌적 고찰 (A Literal Study of the Main Symptoms of Atopic Dermatitis)

  • 김은희;이병욱;김은하
    • 대한한의학원전학회지
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    • 제22권1호
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    • pp.207-228
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    • 2009
  • Objective : To find the main symptoms associated with atopic dermatitis and to get the utmost out of information about cause, treatment are contribute in the treatment of atopic dermatitis rather than looking for ways through how to connect modern atopic dermatitis and a listed symptom of classic literature. Method : In this research, we recorded about the main symptoms of atopic dermatitis such as itch, erythema, edema, pus and furuncle. Also we interpreted original text by extracting a sentence containing the terms like red[赤], pus[膿], flare[發赤], dermatosis[溞], swelling[洋], light red[紅], itch[瀁], worm running[蟲行], juice[汁], rash[癮疹], variegation[疹斑] and summarized cause of symptoms, disease sign, prescription. Results : There are the cause of many symptoms accompanied by atopic dermatitis in the body that recorded unpreparedness[虛], Wind[風], Fever[熱], unpreparedness & interruption of vitality hole[氣穴不通], unpreparedness & Wind, Wind Fever[風熱], Wind Coldness[風寒], Wind Humidity[風濕], Humidity Fever[濕熱], Wind Humidity Fever, Wind of Lungs[肺風], Wind of Lungs and Spleen[脾肺風], the Kidney Wind poison[腎臟風毒], Wind of Lungs Fever, Worm[蟲], miscellaneous vitality[雜氣], unpreparedness and Fever of Heart[心虛熱], old sore of kidney poison[久瘡腎臟風毒].

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조립식 지붕 외장 시스템에 대한 풍하중 평가 (Wind Effects on Loose-Laid Roofing Paver Systems)

  • Ham, Hee-Jung;Lee, Jaehong-
    • 한국전산구조공학회:학술대회논문집
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    • 한국전산구조공학회 1994년도 가을 학술발표회 논문집
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    • pp.47-54
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    • 1994
  • Full-scale and 1:15 scale fluid model experiments of roof ballast pavers are employed to optimize paver geometry and study wind loading and performance of roof ballast pavers. Wind pressures above and beneath pavers are conducted for buildings of different heights and in different flow conditions. The effects of the side hole size and the underneath rib height under the wind loading on pavers and the effects of roof parapet height as well as flow conditions on the performance of pavers are studied. Incorporation of wind tunnel experimental results into code statements is also provided.

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Wind Turbine Tower의 Door 용접부에 대한 피로 강도 연구 (Fatigue Analysis of Welded Toe of Wind Turbine Tower Access Door)

  • 한동영;고장욱;최원호;이승구
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2005년도 춘계학술대회
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    • pp.72-75
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    • 2005
  • Recently, as the global warming by fossil fuels become social issues. the interest of renewable energy producing system is increasing rapidly. Among these, wind turbines are most highlighted because of its economic competitiveness. The tower occupying about $20\%$ of overall turbine costs, is one of the main components of wind turbine. Tower access door located to base part of the tower, is used to enter the tower. This is the main structural weak point because of door hole, weldment, etc. In this study, by FEM, we retrieved the maximum van Mises stress at door location and carried out fatigue analysis using stresses at weld toe locations of tower access door part.

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극지.고산식물 월귤의 격리 분포와 기온요인 (Disjunctive Distribution of Vaccinium vitis-idaea and Thermal Condition)

  • 공우석;임종환
    • 대한지리학회지
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    • 제43권4호
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    • pp.495-510
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    • 2008
  • 월귤은 극지 고산식물로 북극권과 고산대에 주로 자라며, 한반도에서는 북한의 고산대와 아고산대, 남한의 설악산 대청봉과 중청봉 사이 암석지, 귀때기청봉 등 아고산대 그리고 홍천의 산록에 자란다. 월귤이 격리 분포하는 강원도 홍천군 해발고도 350m 부근 애추 말단은 풍혈이다. 플라이스토세 빙하기에 널리 분포했던 월귤은 홀로세에 기후가 온난해지면서 한반도 북부와 중부의 고산대 및 아고산대와 함께 여름이 서늘한 홍천 풍혈 주위를 후빙기 피난처로 삼아 빙하기 유존종으로 격리 분포하게 되었다. 월귤의 남한계선이며 하한계선인 홍천에 자라는 군락은 가장 가까운 거리에 있는 설악산 아고산대와 1,200m의 해발고도 차이가 있으므로 빙하기의 기온은 현재보다 $6.6^{\circ}C$ 내외로 낮았던 것으로 추정된다 극지와 고산에 격리 분포하는 월귤은 여름 고온에 민감한 식물이다. 홍천의 산록에 자라는 월귤은 지구온난화에 따라 생리적으로 영향을 받거나 높은 온도를 좋아하는 식물과의 경쟁에 밀려 사라질 수도 있다. 한반도의 생물다양성 보전 차원에서 홍천의 월귤 군락지에 대한 보호 관리가 필요하다.

원형 손상 구멍이 있는 날개 주위 유동장에 관한 실험적 연구 (An Experimental Investigation on the Flow Field around the Wing Having a Circular Damage Hole)

  • 이기영
    • 한국항공우주학회지
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    • 제36권10호
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    • pp.954-961
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    • 2008
  • 원형 손상구멍이 있는 날개 주위 유동장에 대한 실험연구를 수행하였다. 손상은 시위의 10% 직경의 시위에 수직인 원형 구멍으로, 구멍 중심은 1/4 시위 혹은 1/2 시위에 위치하고 있다. 입자영상유속계에 의한 유동장 측정과 날개의 아래 및 윗면에서의 정압장을 시위를 기준으로 한 레이놀즈수 Rec=2.85×105에서 측정하였다. 입자영상유속계에 의한 유동 측정 결과 손상 구멍 주위에는 두 가지 형태의 유동구조가 형성되었다. 하나는 약한 제트로 손상 구멍 하류에서 부착된 후류가 생성된다. 다른 하나는 받음각 증가에 의한 강한제트에 의한 것으로 손상구멍으로부터 자유흐름으로 관통되어 접근하는 경계층 흐름을 박리시켜 역류가 있는 박리 후류구조를 생성한다. 날개면 압력 자료는 원형 손상 구멍 근처에서 큰 압력변화를 보여주었다. 이러한 압력변화는 손상구멍이 앞전 쪽에 가까울수록 증가하였다.

풍력 발전 시스템 타워의 용접부 강도 연구 (The study for strength of welds of the wind turbine tower)

  • 한동영;안경민;최원호;이승구
    • 한국신재생에너지학회:학술대회논문집
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    • 한국신재생에너지학회 2006년도 춘계학술대회
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    • pp.304-307
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    • 2006
  • Recently, as the global warming by fossil fuels and the steep rise of the oil price become social issues, the interest for renewable energy producing system is increasing rapidly. Among these, the wind turbine is most highlighted because of its economic competitiveness. The tower is one of the main components of wind turbine, which occupying about 20% of overall turbine costs. The tower access door located to base part of the tower, is used to enter the tower. This is the main structural weak points because of door hole, weldment, etc. And so are the weldments between the cans and the flanges. In this study, for the top flange part of the tower, by FEM using ANSYS, we retrieved the maximum von Mises stress on that and carried out fatigue analysis using stresses at such weak points.

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바람 증폭 장치를 가진 태양전지 오염방지시스템의 TRIZ(6SC) 응용 설계 (A Study on TRIZ Applied Design for Contamination Preventation System of Solar Battery with Wind Amplifier)

  • 허용정;홍성도;김재민
    • 반도체디스플레이기술학회지
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    • 제12권2호
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    • pp.7-11
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    • 2013
  • This paper presents a study on the design for contamination preventation system of solar battery. The system of contamination preventation has an wind amplifier. Wind amplifier is conceptually designed by using TRIZ. The surface of solar battery is covered with dust during accumulate the energy. The dust cause reduce power of photovoltaic module and efficiency drop of photovoltaic system. Reflect and absorb of incident ray are caused by the dust on surface of solar battery. The solution of this problem has been derived using 6SC(6 steps creativity)TRIZ. The wind amplifier which has structure such as funnel shape. The incident wind in the wide hole is amplified by the gate become narrow. The system of contamination preventation with wind amplifier which mounted on the side of the solar battery surface reduces the reflect and absorb and improve the efficiency of photovoltaic system.