Study of Mild-Stall Wings with a Fixed Slat

Atsushi Ito,Daisuke Sasaki,Kazuhiro Nakahashi 한국항공우주학회 2008 한국항공우주학회 학술발표회 논문집 Vol.- No.-

Much attention has been paid to PAY (Personal Air Vehicle) as a new-generation small aircraft, It is expected that PAY will be widely used as a short-range transport aircraft in the future for countermeasure against traffic jam, One of the key technologies to make PAY much popular is to enhance the safety, which is crucial to small planes, In order to enhance the safety of PAY, mild-stall high-lift characteristics of the wing are especially needed. This study aims to propose a mild-stall wing with a fixed slat for PAY use, Two mild-stall airfoils are combined to form a new rectangular wing: NACA4415 and SLAT4415, NACA4415 is known as a conventional mild-stall airfoil, and SLAT4415 is a fixed slat airfoil based on NACA4415 for further improvement in stall characteristic, The higher lift characteristic ofSLAT4415 was obtained via the optimization by Genetic Algorithm. Designed wings composed ofNAC4415 and SLAT4415 airfoils are numerically analyzed by solving the Navier-Stokes equations on the unstructured mesh to examine the performance at high-angle of attack for low-speed region, The computational results indicate that designed wings are able to achieve mild-stall characteristics, Lift coefficients of the designed wings tend to drop at 22 degrees of A.o.A, however, increase again as A.o.A becomes higher, For further analysis, numerical simulations for the wing that has a taper or that has only SLAT4415 airfoil were also conducted, As a result, it was proved that the designed rectangular wing that has SLAT4415 airfoil of fixed slat only in outboard wing had very mild stall characteristic.

베네시안 블라인드 슬랫 조절에 따른 에너지 부하의 변동예측

임홍수(Lim Hong-Soo),이정철(Lee Jeong Chul),김곤(Kim Gon) 한국건축친환경설비학회 2008 한국건축친환경설비학회 학술발표대회 논문집 Vol.- No.-

The angles of blinds' slat would change the light environment, so it is necessary to figure out the exact role of the slat adjustment in terms of building energy. As the results of using Radiance and eQUEST program, the angles of blinds' slat for optimal light environment of inside are 30 to 40 degrees in March, 0 degrees in June and 20 degrees in December. In addition, seasonal energy loads of each angles that show the best light environment and the points of energy savings are -20 to 0 degrees in summer and 20 to 40 in winter. However, in the case of 20 to 40 degrees, the opportunity of good view may decrease, compared to when the angle is 0 degrees, and the effect of brightness which stems from slat's surfaces must be considered.

현휘와 에너지성능을 통합 고려한 슬랫형 블라인드의 최적제어 효과에 관한 연구

오명환(Oh Myunh-Hwan),윤종호(Yoon Jong-Ho) 대한건축학회 2012 대한건축학회논문집 Vol.28 No.5

Solar control system is absolutely essential to improve building energy efficiency under the Korean climatic condition which has distinct cooling and heating period. Glass envelope, through which solar heat gain can take place in building, however, is not easy to control. Therefore auxiliary shading devices are necessary to achieve the solar control. Therefore, it is very important to perform research on the high performance shading devices for improving the building energy efficiency because glass envelope is difficult to achieve solar control. According to the advanced research, it is not controled by occupants and is always in the downward position. For solve those problems, the advanced research already have suggested the automated control system of slat-type blind considering visual comport for removing the discomfort glare at window surface and reduction of building energy consumption. As a result, this optimum controled slat-type blind reduced 29.2% energy consumption compared with base case and perfectly removed discomfort glare. Based on this results came up with survey and advanced evaluation, this study purposes to confirm the performance of automated control system of slat-type blind by comparing with 6 alternatives of roll-shade blind classified depending on the visual and solar transmittance. Consequently, this optimum controled slat-type blind reduced energy consumption compared with other roll-shade alternatives and perfectly removed discomfort glare.

슬랫-슬롯을 적용한 임펠러 형상이 송풍기 유동 특성에 미치는 영향

윤종웅,강현수,김윤제 한국유체기계학회 2022 한국유체기계학회 논문집 Vol.25 No.2

A centrifugal fan is commonly used in many industrial applications. This study identified the flow characteristics around the blades applied with slat-slot through a computerized numerical analysis. The impeller with slat-slot and NACA model has goal of to delay the flow separation, and to improve aerodynamic performance. As an indicator for performance evaluation, outlet pressure and mass flow coefficients were selected. The numerical results of the optimized model are graphically analyzed with the coefficients compared with the reference model using the ANSYS CFX. The results show that the optimized model has a better aerodynamic performance than the reference model.

ANN based automatic slat angle control of venetian blind for minimized total load in an office building

Yeon, Sanghun,Yu, Byeongho,Seo, Byeongmo,Yoon, Yeobeom,Lee, Kwang Ho Elsevier 2019 SOLAR ENERGY -PHOENIX ARIZONA THEN NEW YORK- Vol.180 No.-

<P><B>Abstract</B></P> <P>Windows are the only part of a building that can directly penetrate the solar radiation into the occupied space and thus the shading devices are needed to control the solar penetration. A variety of research have been conducted to develop the optimized slat angle control in the existing literature, but the research incorporating artificial intelligence technique with slat angle control is limited thus far. Therefore, in this study, the ANN (Artificial Neural Network) model was applied to minimize the combined total load consisting of lighting, cooling, and heating loads through automatic slat angle control of venetian blinds. A three-story rectangular office building was simulated using EnergyPlus, and dimming control was applied to control the lighting. The interlocked simulation between Matlab and EnergyPlus was conducted through BCVTB. As a result of comparing automatic blind control via the ANN to fixed blind slat angle, the automatic blind control via the ANN showed 9.1% lower total load than the blind angle fixed at 50°. It was confirmed that the cooling and heating load could be significantly reduced by real-time automatic control via the ANN under various operating conditions, rather than fixing the blinds at one angle.</P> <P><B>Highlights</B></P> <P> <UL> <LI> ANN based slat angle control did not cause discomfort glare. </LI> <LI> Optimally controlled blind slat angle using ANN showed slightly higher lighting load than the fixed slat angle cases. </LI> <LI> As a result of the real-time optimal control of blind slat angle through the ANN, the reduction effect of the cooling load was found to be significant. </LI> <LI> When the blind slat angle was optimally controlled through the ANN, the total load reduction effect was shown to be remarkably excellent. </LI> </UL> </P>

SLAT Negatively Regulates RANKL-Induced Osteoclast Differentiation

윤방웅,김낙성,김갑순,김정하,이종원,문장배,김인영,박용욱 한국분자세포생물학회 2013 Molecules and cells Vol.36 No.3

RANKL induces the formation of osteoclasts, which are responsible for bone resorption. Herein, we investigated the role of SWAP-70-like adapter of T cells (SLAT) in RANKL-induced osteoclastogenesis. Expression levels of SLAT were reduced during RANKL-induced osteoclastogenesis. Overexpression of SLAT in BMMs inhibited TRAP-positive multinuclear osteoclast formation and attenuated the expression of NFATc1, which is an important modulator in osteoclastogenesis. Furthermore, silencing of SLAT by RNA interference enhanced osteoclast formation as well as NFATc1 expression. In addition, SLAT was involved in RANKL-induced JNK activation in osteoclasts. Taken together, our data suggest that SLAT acts as a negative modulator of RANKL-induced osteoclastogenesis.

조도 및 차양 슬랫 제어에 의한 조명, 냉방 에너지 사용량 변화 연구

송영학,강두호,박형은,김환용 대한건축학회지회연합회 2023 대한건축학회연합논문집 Vol.25 No.3

Energy consumption in the building sector accounts for about 35% of the South Korea’s total, and several policies and new technologies, products for carbon reduction are being introduced into the market. Slat controlled blinds are a type of technology that can actively respond to solar radiation blocking and lighting load reduction by controlling the angle of the slats installed on the windows of the building. In this study, a conventional-type blinds and slat controlled blinds were installed in two actual rooms, and valid data for 74 days including illumination control were operated to determine the effectiveness of performance by control. The indoor illuminance range of the conventional chamber was about 800~3,400 lux, but the slat controlled blinds chamber was formed at 500~1,400 lux, so the illuminance was stably changed, and as a result, it was confirmed that lighting energy was reduced by 81.5%. In addition, due to the effect of blocking solar radiation by slat control, the cooling energy consumption ratio was reduced by 24.3% during the same period. 건축 부문의 에너지 사용량은 우리나라 전체의 약 35%를 차지하고 있으며, 이로 인해 탄소 저감을 위한여러 정책과 신기술, 제품들이 시장에 도입되고 있다. 집광채광 블라인드는 건물의 실내측 창호부에 설치되며 슬랫의 각도를 조절하여 일사 차단 및 조명 부하 저감에 능동적으로 대응가능한 기술의 하나이다. 본 연구에서는 실제 건물에 2개의 챔버를 설치하고 일반형태의 블라인드와 집광채광 블라인드를 각각 설치하고 74일간의 유효데이터를 확보하여 슬랫 각도와 조도 제어의 유효성을 검토하였다. 기존 챔버의 실내 조도 범위는 800~3400lux였으나 집광채광 블라인드 챔버는 500~1400lux로 형성되어 조도의 변화가 안정적이고 에너지 사용량은 81.5% 절감되는 것을 확인하였다. 또한 슬랫제어를 통해 일사차단 효과가 발생하였고 그 결과 냉방에너지 사용량은 약 23.2% 감소하였다.

스플릿 블라인드의 슬랫 조절 방식에 따른 실내 환경 및 에너지 성능 평가

이규남(Rhee, Kyu-Nam),정근주(Jung, Gun-Joo) 한국건축친환경설비학회 2020 한국건축친환경설비학회 논문집 Vol.14 No.5

The performance of Venetian blinds can be improved by adopting split blinds by which the slat angle in the upper and lower part of the blinds can be separately adjusted. In this study, the impact of the split blinds on the lighting/thermal environment and energy consumption was investigated through field measurement, occupant survey and energy simulation. Four different adjustment methods were evaluated: Case 1 (No blind), Case 2 (All slats open), Case 3 (Upper slats open, lower slats closed), and Case 4 (All slats closed). The evaluation result of lighting environment showed that Case 3 is effective in preventing the excessive illuminance level as well as glare in the winter season, while Case 2 or 3 is suitable for the summer season because the high solar altitude reduces the transmitted solar energy, which leads to the reduced glare risks. The evaluation result of thermal environment revealed that acceptable thermal comfort can be achieved by Case 2 or 3 in the winter season, and Cases 2 to 4 in the summer season. Energy simulation results showed that the overall energy consumption (heating, cooling and lighting energy) can be minimized by applying Case 3, by which the energy consumption can be reduced by 6.2% compared to Case 1.

베네시안 블라인드의 각도 변화에 따른 시간별 일사 투과량 변동에 관한 연구

김동균(Kim Dong-Kyun),김수정(Kim Soo-Jeong),김한용(Kim Han-Yon),김강수(Kim Kang-Soo) 한국건축친환경설비학회 2011 한국건축친환경설비학회 학술발표대회 논문집 Vol.2011 No.3

The purpose of this paper is to calculate hourly transmitted solar radiation in accordance with the change of the slat angle for the venetian blind. For the analysis, e-Quest developed by Department of Energy in U.S.A performed the simulation for the transmitted solar radiation through windows and vertical total solar radiation in the south and west. We set me summer solstice (6/22) and the autumnal equinox (9/23) as a representing clay to analyze me thermal characteristics for the venetian blind. Furthermore, the slat angles of 0, 30, 60, 80 degrees was selected for the simulation. Consequently, the transmitted solar radiation on the south was the highest at 1pm in the summer solstice (6/22) and the autumnal equinox (9/23) when slat angle was 0 degree. However, the transmitted solar radiation on the west was the highest at 6pm in the summer solstice (6/22) and at 5pm in the autumnal equinox (9/23) when slat angle was 0 degree.

Slat Noise Source Modeling of Multi-element Airfoil in High-lift Configuration

Seung Tae Hwang,Chang Kyun Han,Yong Taek Im,Jong Rok Kim,Youngmin Bae,Young J. Moon 한국항공우주학회 2017 International Journal of Aeronautical and Space Sc Vol.18 No.2

We investigate the slat noise generation mechanism by using large-eddy simulation (LES) and simple source modeling based on linearized Euler equations. An incompressible LES of an MD 30P30N three-element airfoil in the high-lift configuration is conducted at Rec = 1.7×10⁶. Using the total derivative of the hydrodynamic pressure (DP/Dt) acquired from the incompressible LES, representative noise sources in the slat cove region are characterized in terms of simple sources such as frequency-specific monopoles and dipoles. Acoustic radiation around the 30P30N multi-element airfoil is effectively computed using the Brinkman penalization method incorporated with the linearized Euler equation. The directivity pattern of p’rms at r = 20cslat in the multiple sources is closely compared to that obtained by the application of the LES/Ffowcs-Williams and Hawking’s methods to the entire flow field. The power spectrum of p’ at θ = 290° is in good agreement with the data reported in BANC-III, especially the broadband part of the spectrum with a decaying slope ∝ f <SUP>-3</SUP>.