• Title/Summary/Keyword: Coupled Cavity

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ANALYSIS ON THE VIBRO-ACOUSTICAL CHARACTERISTICS OF A PANEL-CAVITY COUPLED SYSTEM

  • Kim, Seock-Hyun;Kang, Sang-Wook;Lee, Jang-Moo
    • Journal of Theoretical and Applied Mechanics
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    • v.3 no.1
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    • pp.34-44
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    • 2002
  • Theoretical analysis Is carried out to identify the modal coupling effect between some particular acoustic modes of a vehicle compartment cavity and vibration modes of body panels like side doors, roof or floor. A simplified panel-cavity coupled model is investigated on the coupled resonance frequencies, modes and frequency response characteristics. Through parametric study, It Is possible to explain how the acoustic response of a coupled system will be determined by the vibration and acoustic property of the individual panel and cavity system. Full coupled system shows some interesting features different from those of the semi-coupled system In frequency, mode and acoustic response.

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Applicatio of Finite Element and Boundary Element Methods to Predict Steady-State Response of a Structure-Acoustic-Cavity System (구조-음향계의 정상상태 응답예측을 위한 유한요소법과 경계요소법의 응용)

  • Lee, Cang-Myung
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.20 no.5
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    • pp.1383-1391
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    • 1996
  • The steady-state response for a coupled structure-acoustic-cavity systme has been investigated by numerical technique using a directly coupled finite element method(FEM) and Boundary Element Method(BEM) model. The Laplace tranformed matrix equations for the structure and the acoustic cavity are coupled directly satisfying the necessary equilibrium and compatibility conditions. The coupled FEM-BEM code is verified by comparing its prediction for an example with known analytical, numerical and experimental results. The example involves a coupled structure-acoustic-cavity system which is a box-type cavity with one end as experimentally excited pinned-pinned plate.

Midinfrared Refractive-index Sensor with High Sensitivity Based on an Optimized Photonic Crystal Coupled-cavity Waveguide

  • Han, Shengkang;Wu, Hong;Zhang, Hua;Yang, Zhihong
    • Current Optics and Photonics
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    • v.5 no.4
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    • pp.444-449
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    • 2021
  • A photonic crystal coupled-cavity waveguide created on silicon-on-insulator is designed to act as a refractive-index-sensing device at midinfrared wavelengths around 4 ㎛. To realize high sensitivity, effort is made to engineer the structural parameters to obtain strong modal confinement, which can enhance the interaction between the resonance modes and the analyzed sample. By adjusting some parameters, including the shape of the cavity, the width of the coupling cavity, and the size of the surrounding dielectric columns, a high-sensitivity refractive-index sensor based on the optimized photonic crystal coupled-cavity waveguide is proposed, and a sensitivity of approximately 2620 nm/RIU obtained. When an analyte is measured in the range of 1.0-1.4, the sensor can always maintain a high sensitivity of greater than 2400 nm/RIU. This work demonstrates the viability of high-sensitivity photonic crystal waveguide devices in the midinfrared band.

Performance Analysis of Summertime Heat Transfer Characteristics of the Double Skin Window for Plant Factory (식물공장 이중창호의 하절기 열전달 성능 분석)

  • So, Jae-Hyun;Kim, Woo-Tae
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.24 no.4
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    • pp.351-357
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    • 2012
  • To reduce the summertime cooling load of a plant factory, a concept design was performed for the double skin window which utilizes the low temperature air from a ground coupled heat exchanger. The design parameters were selected as the number of cavity air inlet, the cavity thickness, the location of cavity air inlet, and the configuration of cavity air outlet. A parametric study was conducted in a systematic way to evaluate the heat transfer characteristics of the double skin window. As the number of cavity air inlet and the cavity thickness increase, the heat flux from outside air to indoor air was decreased. The effect of the location of cavity air inlet was not significant and the larger cavity air outlet area gave us relatively better heat blocking performance from outside hot air. This study demonstrated that it is possible to develop an improved double skin window by utilizing a ground coupled heat exchanger.

Equivalent Circuit Parameters of S-band 1.5 Cell RF Gun Cavity

  • Kim, Ki-Young;Kang, Heung-Sik;Tae, Heung-Sik
    • Journal of electromagnetic engineering and science
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    • v.4 no.1
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    • pp.30-36
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    • 2004
  • We determined equivalent circuit parameters of a 1.5 cell S-band RF gun cavity from the resonant characteristics of its decoupled cavities(half cell and full cell) using the code SUPERFISH. Equivalent circuit parameters of the 1.5 cell RF gun cavity resonated in the 0-mode were obtained easily from the circuit parameters of each decoupled cavities. In order to obtain equivalent circuit parameters for the $\pi$ -mode cavity, we calculated the differences of the resonant frequencies and the equivalent resistances between the 0- and $\pi$ -modes with slight variations of the radius and thickness of the coupling iris. From those differences, we obtained R/Q value and equivalent resistance of the $\pi$ -mode, which are directly related to the equivalent circuit parameters of the coupled cavity. Using calculated R/Q value, we can express equivalent inductance, capacitance and resistances of the RF gun cavity resonated in the $\pi$ -mode, which can be useful for analyzing coupled cavities in a steady state.

A Finite Element Analysis of Conjugate Heat Transfer Inside a Cavity with a Heat Generating Conducting Body (고체 열원이 존재하는 공동 내의 복합열전달 문제의 유한요소해석)

  • Ahn, Young-Kyoo;Choi, Hyoung-Gwon;Yong, Ho-Taek
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.3
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    • pp.170-177
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    • 2009
  • In the present study, a finite element analysis of conjugate heat transfer problem inside a cavity with a heat-generating conducting body, where constant heat flux is generated, is conducted. A conduction heat transfer problem inside the solid body is automatically coupled with natural convection inside the cavity by using a finite element formulation. A finite element formulation based on SIMPLE type algorithm is adopted for the solution of the incompressible Navier-Stokes equations coupled with energy equation. The proposed algorithm is verified by solving the benchmark problem of conjugate heat transfer inside a cavity having a centered body. Then a conjugate natural heat transfer problem inside a cavity having a heat-generating conducting body with constant heat flux is solved and the effect of the Rayleigh number on the heat transfer characteristics inside a cavity is investigated.

Aperture Coupled Cylindrical Resonator Oscillator (Aperture Coupled 원통형 공동 공진기 발진기)

  • 나인주;이정해
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
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    • v.14 no.2
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    • pp.119-126
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    • 2003
  • In this paper, a cylindrical cavity resonator oscillator with high Q factor is designed and fabricated to improve the phase noise characteristic. A cavity resonator is coupled to oscillating circuit using aperture hole. Measured results show that the cylindrical cavity resonator oscillator (CRO) for Ku-band has less phase noise than the dielectric resonator oscillator (DRO) with the same oscillating circuit. It has output power of +3.92 dBm at the center frequency 13.4015250 GHz and phase noise of -109 dBc/Hz at 100 kHz offset.

Noise reduction of a vehicle acoustic cavity sample using coupled Structural-Acoustic element analysis (구조-음향 연성해석을 통한 모형차실 모델의 소음저감 기술연구)

  • 김태정;강성종;서정범
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1994.10a
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    • pp.288-294
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    • 1994
  • A study of prediction and qualification techniques for structure borne booming noise is presented in this paper. Result from acoustic normal mode finite element analysis of a 1/2 size vehicle cavity sample model is compared to the that from an experiment. Coupled structural-acoustic analysis is performed on a 1/4 size vehicle cavity sample model surrounded by 2 mm thick normal steel plates. Interior noise levels around passensger's ear position are predicted and reduced by structural modification based on panel participation factor analysis about the sample cavity model. Futhermore, optimization technique in application of anti-vibration pad is studied.

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A Study on the Characteristics of a 400W, 7.9~8.4GHz Double-Slot Coupled-Cavity Traveling-Wave Tube (400W, 7.9~8.4GHz 이중슬롯 결합공진기 진행파관 증폭기 특성 연구)

  • Kim, Hyoung-Jong;Kim, Hae-Jin;Choi, Jin-Joo;So, Jun-Ho
    • Journal of the Korea Institute of Military Science and Technology
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    • v.12 no.6
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    • pp.760-767
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    • 2009
  • This thesis focuses on the study of high-power, coupled-cavity traveling-wave tube(CCTWT) for radar applications. The CCTWT employed a reentrant double-slot staggered RF cavity structure. Computational analysis of the X-band, double-slot staggered structures is carried out through the use of HFSS code, which solves Maxwell's equations fully in three-dimensions. The non-linear, large-signal performance of CCTWTs are predicted from numerical simulations using a three-dimensional particle-in-cell code, MAGIC3D. With beam voltage set to 12.7~13kV and beam current at 300mA, the CCTWT produces a saturated radiation power of 350~430W, corresponding to an electronic efficiency of 8.9~11.2% and a gain of 23.7~24.2dB within a frequency range of 7.9~8.4GHz.

Long-term stabilization of optical feedback of a resonant external cavity coupled semiconductor laser (공진형 외부 캐비티 부착 반도체 레이저의 광피드백 장기 안정화)

  • 신철호
    • Korean Journal of Optics and Photonics
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    • v.9 no.2
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    • pp.96-99
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    • 1998
  • In this study, a novel long term stabilization method of optical feedback for the resonant cavity coupled semiconductor lasers is proposed, and its utility was shown experimentally. The proposed method is realized by using the pahse discriminator of optical feedback with high gain. The phase discriminating signal was obtained by the polarization spectroscopic technique using reflection light from the external reflector, which is a confocal Fabry-Perot cavity. Experimental result shows that stable control state can be maintained up to 20 hours. The period can be increased by reducing size of the system and/or fixing position stably of optical parts used, which were arranged on an optical table by using magnetic bases in this experiment. The proposed long-term stabilization method of optical feedack of a resonant external cavity coupled semiconductor laser is very useful for the field of high sensitivity measurement, and for the use in the laboratory level in particular.

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