• Title/Summary/Keyword: Helical Wave Wire

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A study on the characteristics of wide bandwidth connector for automotive communication (자동차 통신을 위한 광대역 커넥터 특성 연구)

  • Kim, Byeong-Woo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.13 no.1
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    • pp.33-38
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    • 2012
  • In this paper, helical wave wire have been proposed as the vehicle connector for the wireless access in vehicular environments(5.925GHz) communication. This helical slow wave connector is design by considering the properties of critical parameter like helical mean radius, helical pitch, helical wire radius and distance of helical wire to shield. The design simulation and results can be used to determine the most suitable helical wave wire dimensions for vehicle communication connector. The optimized WAVE connector inserted the helical wave wire has insertion loss less than -0.76dB at 5.925GHz. It provides 31% of insertion loss with good performance. Therefore, the simulated results can be effectively used for optimum design of high frequency connector for vehicle communication.

Wave Motion of Helical Springs with a Circular Section (원형 단면을 갖는 헬리컬 스프링에 대한 파동)

  • Lee, Jae-Hyeong;Heo, Seung-Jin
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.5
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    • pp.866-873
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    • 2001
  • The governing partial differential equations of a helical spring with a circular section were derived from Frenet formulas and Timoshenko beam theory. These were solved to give the dispersion relationship between wave number and frequency along with wave form. Wave motions of helical springs are categorized by 4 regimes. In the first regime, the lower frequency area, the torsional and extensional waves of the spring are predominant and two waves are composite wave motions involving lateral motion of the coils and rotation of the coils about a horizontal axis. All waves are propagating in the second regime. The wave of the extensional motion of the spring and one wave of transverse motion of a wire change from travelling waves to near field waves in the third regime. Both waves excited by both axial and transverse motion are predominant in the fourth regime.

Helical Instability Wave Excitation of Swirling Jets (스월제트에 관한 헬리컬 불안정파 자극)

  • Lee, Won-Joong;Taghavi, Ray-R.
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.33 no.1
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    • pp.48-53
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    • 2005
  • The purpose of this investigation is to explore the possibility of using artificial mechanical means for excitation of shear layers with application in swirling jet mixing enhancement. For this purpose, a mechanical excitation device was designed and fabricated. The major system components consist of two subsonic nozzles, one swirl generator, and the excitation device. The experiments were carried out at various helical excitation modes; i.e., m=+0, m=$\pm$1, m=$\pm$2, m=$\pm$3, and m=$\pm$4. Axial mean velocity measurements were made with plane and helical wave excitation using a hot-wire anemometer. The results are compared with the baseline (plane-wave excitation) at various helical modes. The acquired data is presented in 3-D mesh plots and 2-D contour plots. It was observed that new device was effective in excitation of the helical instability waves and resulting in mixing enhancement of the swirling jet.

Experimental Study on the Enhancement of Condensation Heat Transfer on a Single Horizontal Tube Utilizing EHD (전장을 이용한 수평관 주위에서의 응축 열전달촉진에 관한 실험적 연구)

  • 유갑종;추홍록;김석준;이성진
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.11
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    • pp.3008-3020
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    • 1994
  • Condensation heat transfer on a single horizontal tube with electric fields (Electro-Hydro-Dynamics, (EHD)) has been studied experimentally. Results are presented for EHD enhanced condensation of R-113 on a single horizontal tube using several electrode geometries. Especially, its attention was focused on the effects of electrode geometry, electric field strength and the gap of the electrode. In this study, single wire, helical, ring and mesh electrode were used. The range of the imposed voltage was 0~20 kV. As the voltage was increased the surface of liquid became an unstable wave, stream jet, liquid column and then liquid extraction in sequence. Among the various kinds of electrodes, the single wire electrode is suitable for practical application.