• 제목/요약/키워드: cylindrical/circular ridges

검색결과 2건 처리시간 0.014초

Effect of stall delay characteristics of symmetrical aerofoil using lateral circular ridges

  • Raatan, V.S.;Ramaswami, S.;Mano, S.;Pillai, S. Nadaraja
    • Wind and Structures
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    • 제34권4호
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    • pp.385-394
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    • 2022
  • Global Warming has been driven majorly by the consumption of fossil fuels. Harnessing energy from wind is viable solution towards reducing carbon footprint created due to burning such fuels, However, wind turbines have their problems of flow separation and aerodynamic stall to tackle with. In an attempt to delay the stall angle and improve the aerodynamic characteristics of the NACA 0015 symmetrical aerofoil, lateral cylindrical ridges were attached to its suction surface, at chord positions ranging from 0.1c to 0.5c. The characteristics of the original and ridged aerofoils were obtained using simultaneous pressure readings taken in a wind tunnel, at a free stream Reynolds number of Re = 2.81 × 105 for a wide range of free stream angles of attack ranging from -45° to 45°. Depending on the ridge size, a delay in stall angle varying from 5° to 20° was achieved together with the maximum increase in lift in the post-stall phases. Additionally, efforts were made to identify the optimum position for each ridge.

내부에 두 개의 융기부를 가지고 표면에 방사슬롯을 갖는 원통형 안테나 (A Cylindrical Reentrant Cavity with a Circumferential Slot as an Antenna)

  • 채규수;임중수
    • 한국산학기술학회논문지
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    • 제6권5호
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    • pp.407-411
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    • 2005
  • 본 논문에서는 원통 실린더 내부의 아래와 윗면에 융기부가 있고 원통의 가운데 면을 따라 슬롯이 있는 구조에 대한 모사 연구이다. 이 연구는 두 융기부나 슬롯의 크기를 조절하여 원통의 크기를 0.3파장으로 줄일 수 있음을 보여주고 있다. CST MWS를 이용한 모사 결과는 이론적인 예측과 비슷한 결과를 보여주고 전기적으로 작은 안테나의 연구에 중요한 역할을 할 것으로 사료된다.

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