• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2012년도 제38회 춘계학술대회논문집
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• pp.324-330
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• 2012

Dual bell nozzle is one of the most promising choices among the altitude adaptation nozzles. This facilitates having a forced, steady and symmetrical separation at lower altitudes and a controlled flow separation at the wall inflection point which prevents the generation of dangerous side loads. In order to ensure the attached flow in the second bell, a clear understanding of the flow transition is required. Hence the motivation of our study is to arrive at an optimum profile for the second bell, which allows a sudden and controlled transition. In this work, we designed the first bell using the conventional MoC and the second bell using an inverse MoC, imposing a pressure gradient constraint. A CFD analysis is also carried out. It is found that the separation point is near the inflection point within one fourth of the extension length or it is near the exit.

• Wind and Structures
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• 제32권4호
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• pp.393-403
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• 2021

A comprehensive knowledge of the wind flow in hilly terrains is of great interest in many engineering applications, be it wind energy distribution for suitable site selection for wind farms, pollution dispersion, forest fire propagation or agrometerological studies. Several researchers have shown that wind flow over a hilly terrain may be significantly different when compared with the wind flow over a flat terrain. Complex hilly terrains may alter the wind speed to a great extent. Therefore, this effect of terrain must be properly assessed by designers and planners to arrive at a proper wind flow distribution. This paper reviews the work done in this area over the past three decades. Wind flow over two-dimensional hills and two-dimensional escarpments investigated in wind tunnels by various researchers is presented in this paper.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집D
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• pp.559-564
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• 2001

Advanced gas turbine engines employ turbine entry temperatures so high that cooling of the turbine blades is essential. The coolant flow introduces losses which need to be minimized, and therefore it is important that the minimum amount of coolant is used. This work presents the result of the one-dimensional analysis and the effect of the boundary conditions on coolant flow rate in gas turbine blades.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.48-53
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• 1995

Recently, work of construction industry is not enough to do in tamping because of a lack of expert, advanced-age of worker, increase of structure of high-dengity arrangment and machanization of concrete pumping method Accordingly it is required for high-qualuily concrete with excellent flowability, Self-placeability and regregation registance. In this point of view, this study is investigated for requiremend properties of ultar-flow concrete using dimestic material as for development of Ultra-Flow concrete in the side of material

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2005년도 연구개발 발표회 논문집
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• pp.437-440
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• 2005

In the present work, characteristics of the flow in CAGE of a steam turbine LP/HP Bypass control valve for thermal power plant are investigated. The flow field is analyzed numerically by solving steady three-dimensional Reynolds-averaged Navier-Stokes equations. Shear stress transport (SST) model is used as turbulence closure.

• 설비공학논문집
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• 제13권9호
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• pp.888-894
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• 2001

Advanced gas turbine engines employ turbine entry temperatures so high that cooling of the turbine blades is essential. The coolant flow introduces losses which need to be minimized, and therefore it is important that the minimum amount of coolant should be used. This work presents the result of the one-dimensional analysis and the effect of the boundary conditions on coolant flow rate in gas turbine blades.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.294.1-294.1
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• 2003

At pH 7.4 (physiological pH), skin is permselective to cations, due to the net negative charge of the current passing channels (pores) in skin. This causes the convective solvent flow (electroosmotic flow) from anode to cathodal direction. In this work, we have investigated several factors (pH. current density and ionic strength) that can affect the electroosmotic flow. (omitted)

• 한국지리정보학회지
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• 제11권1호
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• pp.138-154
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• 2008

1996년부터 3단계 국가GIS 5개년 계획이 시행되고 있는 현재까지 지리정보기술은 다양한 분야에 활용되고 있으나, 그 기술의 근간이 되는 지리공간자료의 최신성과 정확성을 확보할 수 있는 체계를 갖추지 못하고 있다. 지리공간자료(수치지형도, 수치주제도)와 관련된 업무는 지형지물의 변화 발생에서 부터 자료수집, DB 구축, 유통, 공유 등 모두가 개별적으로 이루어지고 있다. 이와 같은 개별구조를 하나의 흐름으로 연계하여 효율적이고 체계적인 업무처리가 이루어질 수 있도록 일관성 있는 모형개발이 요구되고 있다. 본 연구에서는 대구광역시를 사례로 지리공간자료의 경제적 갱신과 교환 방안을 제시하고, 기존의 업무수행 절차와 비교하여 비용편익분석을 실시하였으며, 그 결과를 이용하여 모형을 개발하였다.

• 대한방사선협회지
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• 제25권1호
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• pp.99.2-100
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• 1999

• 대한심미치과학회지
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• 제21권1호
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• pp.83-92
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• 2012