• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.209-215
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• 2001

The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and no stray currents, Hence, flow into the Pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. But various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall and back-wall due to different clearances from back-wall to vertical in take pipe. Moreover, the locations and vorticities of the various types of vortices that were found in the examinations are discussed.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집B
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• pp.563-569
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• 2001

The head-capacity curves for pumps developed by the pump manufacturer are based on tests of a single pump operating in a semi-infinite pool with no nearby walls or floors and no stray currents, Hence, flow into the pump suction is symmetrical with no vortices or swirling. Pump station designers rely on these curves to define the operating conditions for the pump selected. But various constraints such as size, cost, and limitations on storage time require walls, floors, and pump intakes to be close proximity to each other. From this background, the authors are carrying out a systematic study on the flow characteristics of intakes within a sump found in pump stations. Model pump intake basin is designed and PIV is adopted as a measuring tool to capture the instantaneous flow patterns. Special attention is paid to investigate the flow patterns near the free surface, side-wall and back-wall due to different clearances from back-wall to vertical in take pipe. Moreover, the locations and vorticities of the various types of vortices that were found in the examinations are discussed.

• Earthquakes and Structures
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• 제18권4호
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• pp.451-466
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• 2020

In this paper, the effect of Engineered Cementitious Composites (ECC) on the lateral strength of a bearing unreinforced Masonry (URM) wall, was experimentally and numerically investigated. Two half scale solid walls were constructed and were tested under quasi-static lateral loading. The first specimen was an un-retrofitted masonry wall (reference wall) while the second one was retrofitted by ECC mortar connected to the wall foundation via steel rebar dowels. The effect of pre-compression level, ECC layer thickness and one or double-side retrofitting on the URM wall lateral strength was numerically investigated. The validation of the numerical model was carried out from the experimental results. The results indicated that the application of ECC layer increases the wall lateral strength and the level of increment depends on the above mentioned parameters. Increasing pre-compression levels and the lack of connection between the ECC layer and the wall foundation reduces the influence of the ECC mortar on the wall lateral strength. In addition, the wall failure mode changes from flexure to the toe-crashing behavior. Furthermore, in the case of ECC layer connected to the wall foundation, the ECC layer thickness and double-side retrofitting showed a significant effect on the wall lateral strength. Finally, a simple method for estimating the lateral strength of retrofitted masonry walls is presented. The results of this method is in good agreement with the numerical results.

• 대한설비공학회지:설비저널
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• 제17권4호
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• pp.382-394
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• 1988

Dynamic characteristics of thermally-forced stratification process in a square enclosure with a linear temperature profile at the side walls have been investigated through flow visualization experiment and numerical analysis. The experiment was performed on air with the Rayleigh numbers of order $10^5$. A particle tracer method is used for the flow visualization and to obtain a sudden linear temperature profile at the side walls copper blocks which already have a linear temperature profile are come into contact with the thin copper plates of the test section. Immediately a meridional circulation is developed and heat transfer takes place from the wall to the interior region by circulation of fluid and finally a thermal stratification is achieved. In the numerical study, QUICK scheme for convective terms, SIMPLE algorithm for pressure correction, and the implicit method for the time marching are adopted for the integration of conservation equations. Comparison of flow visualization and numerical results shows that the developing flow patterns are very similar in dynamic nature even though there is a time lag due to the inevitable time delay in setting up a linear temperature profile. For high Rayleigh numbers, the oscillatory motion is likely to take place and stratified region is extended. However, initial temperature adjustment process is much slower than that for low Rayleigh numbers.

• Advances in Computational Design
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• 제4권3호
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• pp.223-238
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• 2019

This study investigated the ultimate lateral load capacity of shear walls constructed with several types of structural foam sheathing. Sixteen tests were conducted and the results were compared to the published design values commutated by the manufactures for each test series. The sheathing products included 12.7 mm (1/2 in) SI-Strong, 25.4 mm (1 in) SI-Strong, 12.7 mm (1/2 in) R-Max Thermasheath, and 2 mm (0.078 in) ThermoPly Green. The structural foam sheathing was attached per the manufacturers' specification to one side of the wood frame for each wall tested. Standard 12.7 mm (1/2 in) gypsum wallboard was screwed to the opposite side of the frame. Simpson HDQ8 tie-down anchors were screwed to the terminal studs at each end of the wall and anchored to the base of the testing apparatus. Both monotonic and cyclic testing following ASTM E564 and ASTM E2126, respectively, were considered. Results from the monotonic tests showed an 11 to 27 percent smaller capacity when compared to the published design values. Likewise, the test results from the cyclic tests showed a 24 to 45 percent smaller capacity than the published design values and did not meet the seismic performance design criteria computation.

• 한국음향학회지
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• 제37권5호
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• pp.356-362
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• 2018

장방형 평면의 한쪽 끝에 자리잡아 벽체와 천장 등의 1차 혹은 2차반사음을 많이 확보할 수 있는 슈박스 콘서트홀의 무대와는 달리, 객석으로 둘러싸인 무대의 빈야드 콘서트홀은 무대 위의 연주자들이 자신이나 다른 연주자들의 연주음 크기나 화음을 모니터링 할 수 있는 초기반사음이 절대 부족하다. 무대 주변벽에서의 반사음을 기대할 수 있지만 무대라이저와 그 위의 연주자들에 의해 상당부분 가려지기 때문에 그 효과는 극히 제한적이다. 무대반사판(ensemble reflector)은 무대의 상부에 설치하여 연주자들의 모니터링을 가능하게 함으로써 연주음의 앙상블을 향상시키는 데 기여할 수 있는 효과적인 수단이다. 2,000여석 규모의 커다란, 따라서 높은 천장으로 인해 유효한 초기 천장반사음을 확보하기 힘든 대형 빈야드 콘서트홀에서 적절한 위치와 형태와 면적을 갖는 효율적인 무대반사판을 설계하고 무대서포트에 관한 정량적 지표를 토대로 그 효과를 검증하였다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.20-21
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• 2006

Three kinds of jet flows encountered in the practical airframe design phase are discussed in this paper. Firstly, the side jet effect on the cavity flow over the flat plate was investigated. Secondly, the aerodynamic modeling of side jet influence on body-tail configuration was presented. Computational study of the similarity parameters was done to minimize the wind tunnel test. Lastly, supersonic jet impingement on a flat plate surrounded by solid walls was simulated numerically for both axi-symmetric and three-dimensional calculations with moving body method.

• 한국안전학회지
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• 제27권3호
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• pp.104-110
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• 2012

It is a common practice to design basement walls acting as a one-way slab or plate with idealized boundary conditions, resulting in potentially inefficient design. The walls are often supported by buttress columns and side walls in the vertical direction, thereby acting as a two-way slab. In this study, structural behavior of single-story, three-span basement wall subjected to lateral soil pressure was investigated. Three dimensional finite element analyses were conducted to determine the force distribution on the wall. Based on the numerical studies, a regression analysis was carried out to determine the design values of moments in vertical and horizontal directions as well as shear forces on the wall and design charts are developed. The proposed design method with accompanying design charts would enable practicing engineers to estimate member forces on the wall for preliminary design purpose without resorting to finite element analysis. Numerical examples demonstrated the applicability of the proposed method.

• 건축역사연구
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• 제23권4호
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• pp.47-56
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• 2014

Traditional wall is ground coat, twice plater, last plaster by such a process has made a wide variety of used materials and techniques are accordingly diverse. These traditional techniques handed down the traditional walls of the techniques, rather than coming to the lowered cut off at any moment from now when the technique is used, not knowing whether to be used. Repair and restore cultural property maintenance work, it is not only the outward form hiding inside it is a technique to keep the preservation of cultural assets can be called true. When viewed from the side walls of these conventional techniques to reveal changes in the traditional process by looking at the changes in technology with traditional techniques for cause shall be made in stock. This paper is from the late Joseon Japanese occupation of techniques ranging from traditional wall to reveal the change process to its current significance of cultural property repair method to be helped.

• 대한기계학회논문집
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• 제17권2호
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• pp.458-466
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• 1993

Natural convection in trapezoidal sections of cavity was numerically investigated using a Finite Volume Method. Temperatures of the upper inclined and lower horizontal walls are constant, with vertical side walls being insulated. When the top wall is hotter than the bottom one, a single cell of stratified flow field is obtained and heat transfer occurs only by conduction. For the colder top wall, bifurcation solutions are obtained for the higher Rayleigh numbers, while unique solutions for lower values. Flow structure is strongly dependent on the configuration and the Rayleigh number.