• Title/Summary/Keyword: Spoiler

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A study on the Aerodynamic Characteristics of a Multi-Functional Spoiler (다기능 spoiler의 공력특성에 관한 연구)

  • Lee, B.J.;Sheen, D.J.;Kim, W.J.
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.8 no.1
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    • pp.67-81
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    • 2000
  • An experimental study was performed on the time lag, lift and drag characteristics of a multi functional spoiler which is a device to increase lift and drag contrary to conventional spoiler which decrease lift and increase drag. In this study, a wind tunnel investigation was made of the effect of incidence angle, slot width, and chordwise location of multi functional spoiler on the time lag, lift and drag characteristics of a wing. The results indicate that the time lag of a multi functional spoiler is influenced mainly not only by the chordwise location of a spoiler but also by the slot width between spoiler and wing upper surface. Multi functional spoiler can reduce time lag effectively by slotting the trailing edge of spoiler with slot ratio (slot width devided by the wing chord length) between 0.05 and 0.1. Also, it shows that the lift and drag coefficients of the wing with the multi functional spoiler and trailing edge flap are increased by 20% and 80%, respectively, compared to the wing with trailing edge flap only.

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Experimental Study on Drag Reduction of Ground Vehicle Using a Rear-Spoiler (Rear-spoiler를 이용한 자동차의 항력감소에 관한 실험적 연구)

  • 최재호;이상준
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.3
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    • pp.31-39
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    • 1996
  • The effect of rear-spoiler attached at rear end of automobile trunk on the aerodynamic characteristics of a MIRA reference car model was experimentally investigated. For different shapes and positions(G/H) of the rear-spoiler, the aerodynamic forces on the automobile were measured at various flow speed(ReL). The effect of rear-spoiler on the wake structure behind the automobile was also investigated using flow visualization and hot-wire anemometer. The rear-spoiler modifies the near wake structure and decreases aerodynamic drag and increases driving stability compared with those of the conventional automobile without rear-spoiler. From the experimental results, rear-spoiler of airfoil shape installed at the position of G/H=0.084 shows the best aerodynamic performance.

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두경부암의 6MV 광자선 치료 시 표면선량 증가를 위한 Spoiler의 유용성 평가

  • 이강혁;김원택;이화중;김대영
    • The Journal of Korean Society for Radiation Therapy
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    • v.14 no.1
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    • pp.41-47
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    • 2002
  • 1.목적 두경부암(head and neck Ca)과 쇄골상부(Supraclavicular)에 6MV 광자선으로 치료 시 치료부위(Target volume)가 피부에서 대략 $1^{\sim}2mm$정도 깊이에 위치할 경우, 6MV 광자선의 선량분포는 표면선량이 낮아서 치료에 적합하지 않기 때문에 Bolus와 같이 사용하지만 Skin Sparing(피부보호)효과의 손실로 피부의 손상이 발생할 수 있다. 이러한 이유로 피부의 보호와 치료 시 표면선량의 증가를 위해 Spoiler(산란판)를 제작하여 측정 후 그 특성을 이해하고 선량의 분포를 통하여 Bolus와 비교한 후에 Spoiler의 유용성에 대해 평가하고자 하였다. 2.방법 Siemens사 선형가속기(PRIMUS)의 6MV 광자선을 사용하여 Spoiler의 사용여부 및 Spoiler의 사용 시에는 조사면의 크기를 $5{\times}5,\;7{\times}7,\;10{\times}10,\;15{\times}15,\;20{\times}20cm^2$로 하고 Spoiler와 표면과의 거리는 6, 10, 15cm로 바꾸어 가면서 물팬톰(PTW. 독일)을 이용해 깊이와 측방에 따른 선량분포를 Markus 전리함(PTW. 독일)으로 측정하였으며 전리함의 방수를 위해 씌어진 방수 캡 때문에 표면선량을 별도의 고형 팬톰으로 측정하였다. 표면의 측정선량은 전리함의 측면 벽 등에 의한 선량 측정치의 증가 현상으로 과 반응을 보였으며 이를 교정하였다. 그리고 측정된 데이터를 치료계획 시스템(Pinnacle 6.0m)으로 비교, 분석하였다. 3.결과 Spoiler의 사용 시 3cm깊이 측정선량 백분율과 Spoiler를 사용하지 않은 해당 치료 조사면의 3cm깊이 선량의 백분율에 일치하도록 하여 가상의 치료 깊이인 2mm에서 측정값을 비교하여 본 결과 조사면 $5{\times}5,\;10{\times}10,\;20{\times}20cm^2$에서 OPEN시 62, 64, $70\%$, Bolus는 97, 97, $99\%$로 Spoiler의 사용 시 표면과의 거리가 6cm에서 82, 98, $103\%$, 10cm에는 72, 89, $101\%$, 15m에 65, 79, $96\%$로 나타났으며 표면에서의 측정값을 비교하여 본 결과 OPEN시 11, 17, $27\%$, Bolus는 84, 84, $86\%$, Spoiler의 사용 시 6cm에서 40, 71, $93\%$, 10cm에는 25, 50, $81\%$, 15cm에 18, 36, $67\%$를 나타내었다. 또한 3m깊이에서의 측방 선량분포에서 Spoiler의 거리변화(6, 10cm)는 심부선량의 변화에 영향을 주지 않는 것으로 확인할 수 있었다. 그리고 위의 실험측정치를 치료계획 시스템에 입력하여 선량분포를 확인한 결과 Spoiler를 사용하는 경우 OPEN에 비해 선량분포 영역을 표면으로 끌어 올릴 수 있으며 Bolus 보다 피부 보호효과는 어느 정도 유지가 되는 것을 보여주었다. 4.결론 이와 같이 Spoiler는 Bolus와 비교하여 6MV 광자선의 build up 영역을 표면으로 증가시키는 동시에 Skin Sparing(피부보호)효과를 유지할 수 있으며 두경부암의 치료에서 Spoiler의 사용이 가능한 조건으로는 조사면이 $5{\times}5cm^2$에서 Spoiler와 표면과의 거리가 6cm일 때, $7{\times}7cm^2$에서 6cm, 10cm였고 $10{\times}10cm^2$는 10cm, 15cm로, $15{\times}15cm^2$는 15cm의 간격으로 평가되었다. 또한 $20{\times}20cm^2$의 조사면, Spoiler가 6cm 간격 인 경우 Bolus를 사용한 것 보다 더욱 높은 표면선량을 나타내었다. 그러나 Spoiler와 표면간의 거리를 다르게 함으로써 깊이에 따라 선량분포를 다양하게 나타낼 수 있기 때문에 표면선량의 증가와 피부의 보호를 위해 환자의 피부 두께, 실제 치료 부위의 깊이 등을 고려한다면 Spoiler를 사용하는 것이 bolus를 사용하는 것보다 더 유용하게 적용할 수 있을 것으로 사료된다.

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The study about aerodynamics according to the spoiler of the car (자동차 Spoiler의 유무에 따른 공력 특성 비교 분석)

  • Kim, Wang-Hyeon;Kim, In-Hyeon;Ryu, Gi-Myeong;Kim, Byeong-Su
    • Proceeding of EDISON Challenge
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    • 2013.04a
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    • pp.421-424
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    • 2013
  • 본 연구에서는 교육 및 연구를 위한 CFD 해석 프로그램인 EDISON_CFD를 이용하여 자동차 Spoiler의 장착 유무에 따른 공력 특성을 분석해보았다. Spoiler가 장착되지 않은 자동차의 공력 특성을 확인하고, Spoiler의 길이에 따라 공력 특성이 어떻게 차이가 나는지 비교하였다. HONDA S2000 차량의 압력 계수를 구하였고, 자동차 길이의 3.5%, 7%, 14%에 해당하는 길이의 Spoiler를 장착하여 어떠한 변화가 발생하는지 확인하였다. 그 결과 Spoiler의 길이가 길수록 짧을 때보다 상대적으로 좋은 효율을 보이는 것을 확인할 수 있었다.

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Monte Carlo Based Planning System for a Beam Spoiler

  • 강세권;조병철;박희철;배훈식
    • Proceedings of the Korean Society of Medical Physics Conference
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    • 2003.09a
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    • pp.56-56
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    • 2003
  • For the treatment of superficial tumors like squamous cell carcinoma of the head and neck, 6 MV photon beam is not appropriate and a spoiler is widely used to increase dose in the buildup region, while preserving the skin sparing effect. However, commercially available treatment planning systems assume a normal unspoiled beam, thereby cannot predict the buildup dose with spoiler accurately. We aimed to implement a Monte Carlo (MC) based planning system to apply it to the radiation treatment of head and neck. Lucite with thickness of 10-mm was used for the beam spoiler with Siemens Primus 6 MV photon beam. BEAM/DOSXYZ MC system was employed to model the linac and the spoiler. To verify the calculation accuracy of MC simulations, the percent depth doses (PDDs) and profiles with and without spoiler were measured using a parallel-plate chamber. For the MC based planning, we adopted a hybrid interface system between Pinnacle (Philips, USA) and BEAM/DOSXYZ to support treatment parameters of Siemens linac and the spoiler. The measurements of PDDs and profiles agreed with the corresponding MC simulations within 2% (lSD), which demonstrate the reliability of our MC simulations. The spoiler generated electrons make a contribution to the absorbed dose up to depth of 2cm, which shows that the dominant source of increased dose from spoiler system is the contaminating electrons created by the spoiler. The whole procedures necessary for MC based treatment planning were performed seamlessly between Pinnacle and BEAM/DOSXYZ system. This ability helps to increase the clinical efficiency of the spoiler technique. In conclusion, we implemented a MC based treatment planning system for a 6 MV photon beam with a spoiler. We demonstrate sophisticated MC technique makes it possible to predict dose distributions around buildup region accurately.

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Parametric Study of Transient Spoiler Aerodynamics with Two-Equation Turbulence Models (2-방정식 난류모델을 이용한 스포일러 천이적 공력특성의 파라메트릭 연구)

  • Choi S. W.;Chang K. S.;Ok H. N.
    • 한국전산유체공학회:학술대회논문집
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    • 2000.10a
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    • pp.15-24
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    • 2000
  • The transient response of an airfoil to a rapidly deploying spoiler is numerically investigated using the turbulent compressible Navier-Stokes equations in two dimensions. Algebraic Baldwin-Lomax model, Wilcox $\kappa-\omega$ model, and SST $\kappa-\omega$ turbulence model are used to calculate the unsteady separated flow due to the rapid spoiler deployment. The spoiler motion relative to a stationary airfoil is treated by an overset grid hounded by a Dynamic Domain-Dividing Line which has been devised by the authors. The adverse effects of the spoiler influenced by the spoiler location and the hinge gap are expounded. The numerical results are in reasonably good agreement with the existing experimental data.

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Skin Dose Distributions with Spoiler of 6MV x-ray for Head and Neck Tumor (두경부암 치료를 위한 6MV X-선 산란판의 제작과 산란분포 측정)

  • Lee, Ho-Soo;Lee, Jong-Keol;Lee, Byung-Jun
    • The Journal of Korean Society for Radiation Therapy
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    • v.7 no.1
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    • pp.176-184
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    • 1995
  • It is very useful benefits to use the megavoltage photon beams in deep site tumor radiotherapy for skin sparing effects. But, In some cases of head and mock tumors, it is often necessary to use spoiler for rapid buildup on skin region. A spoiler with tissue equivalent material to be moved between the patients and the collimator can increase or control the skin dose and buildup region due to position and thickness of the spoiler was measured. Then, the effect of spoiler on skin dose and build up region in protruded tumor of head and neck was evaluated quantitatively. The measurements were abtained with PTW 2334 chamber (Markus type) on a polystylene phantom for 6MV x-ray from an accelerator.

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Influence of a rear spoiler on a squareback car wake (리어 스포일러 장착에 의한 자동차 후류의 변화 연구)

  • Baek, Seung-Jin;Oh, Min-Soo;Lee, Jung-Ho;Kim, Moo-Sang
    • Proceedings of the KSME Conference
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    • 2004.04a
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    • pp.1825-1829
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    • 2004
  • A numerical simulation was performed of flow behind a squareback car with a rear spoiler. Influence of the rear spoiler on drag force has been studied. A lattice Boltzmann method was utilized to portray the unsteady aerodynamics of wake flows. The pressure distributions were employed to examine the vortex formation mode against the rear spoiler. It was found that the separation flow at roof end and c-pillar makes three dimensional vortex structures and the rear spoiler increases pressure on the rear glass surface.

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Unsteady Flow Computation of a ]Rapidly Deploying Spoiler (빠르게 전개되는 스포일러의 비정상 유동해석)

  • Choi S. W.;Chang K. S.
    • 한국전산유체공학회:학술대회논문집
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    • 2000.05a
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    • pp.127-139
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    • 2000
  • Transient aerodynamic response of an airfoil to a rapidly deploying spoiler is numerically investigated using a two-dimensional turbulent compressible Navier-Stokes flow model. The spoiler moving relative to a stationary airfoil is treated by an overset grid bounded by a 'dynamic domain-dividing line' the concept of which is developed first..in this paper. The fluid-dynamic mechanism of the adverse lift due to the rapidly deploying spoiler is analyzed. Also the effect of spoiler deploying rate on the initial behavior of the aerodynamic response is expounded, which is of interest in view of active control technology and controller design for the spoiler. The results of present computation about the stationary as well as moving spoilers are relatively in good agreement with the existing experimental data.

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Effects of the Air Spoiler on the Wake Behind a Road Vehicle by PIV Measurements (자동차 후류에서 에어스포일러의 영향에 대한 PIV 측정)

  • Kim, Jin-Seok;Sung, Jae-Yong;Kim, Jeong-Soo;Choi, Jong-Wook;Kim, Sung-Cho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.2 s.245
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    • pp.136-143
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    • 2006
  • A particle image velocimetry (PlV) technique has been applied to measure the quantitative flow field characteristics behind a road vehicle with/without an air spoiler attached on its trunk and to estimate its effect on the wake. A vehicle model scaled in the ratio of 1/43 is set up in the mid-section of a closed-loop water tunnel. The Reynolds number based on the vehicle length is $10^5$. To investigate the three-dimensional structure of the recirculation zone and vortices, measurements are carried out on the planes both parallel and perpendicular to the free stream, respectively. The results show significant differences in the recirculation region and the vorticity distributions according to the existence of the air spoiler. The focus and the saddle point, appearing just behind the air spoiler, are disposed differently along the spanwise direction. Regarding the streamwise vortices, the air spoiler produces large wing tip vortices. They have opposite rotational directions to C-pillar vortices which are commonly observed in case that the air spoiler is absent. The wing tip vortices generate the down-force and as a result, they can make the vehicle more stable in driving.