• Title/Summary/Keyword: 도파관유한요소법

Search Result 36, Processing Time 0.028 seconds

Vibration of Pipes Coupled with Internal and External Fluids (내부 및 외부 유체와 연성된 파이프의 진동 해석)

  • Ryue, Jung-Soo
    • The Journal of the Acoustical Society of Korea
    • /
    • v.31 no.3
    • /
    • pp.142-150
    • /
    • 2012
  • The waveguide finite element (WFE) method is a useful numerical technique to investigate wave propagation along waveguide structures which have uniform cross-sections along the length direction ('x' direction). In the present paper, the vibration and radiated noise of the submerged pipe with fluid is investigated numerically by coupling waveguide finite elements and wavenumber boundary elements. The pipe and internal fluid are modelled with waveguide finite elements and the external fluid with wavenumber boundary elements which are fully coupled. In order to examine this model, the point mobility, dispersion curves and radiated power are calculated and compared for several different coupling conditions between the pipe and internal/external fluids.

A Numerical Method for Analysis of the Sound and Vibration of Waveguides Coupled with External Fluid (외부 유체와 연성된 도파관의 진동 및 소음 해석 기법)

  • Ryue, Jung-Soo
    • The Journal of the Acoustical Society of Korea
    • /
    • v.29 no.7
    • /
    • pp.448-457
    • /
    • 2010
  • Vibrations and wave propagations in waveguide structures can be analysed efficiently by using waveguide finite element (WFE) method. The WFE method only models the 2-dimensional cross-section of the waveguide with finite elements so that the size of the model and computing time are much less than those of the 3-dimensional FE models. For cylindrical shells or pipes which have simple cross-sections, the external coupling with fluids can be treated theoretically. For waveguides of complex cross-sectional geometries, however, numerical methods are required to deal with external fluids. In this numerical approach, the external fluid is modelled by the boundary elements (BEs) and connected to WFEs. In order to validate this WFE/BE method, a pipe submerged in water is considered in this study. The dispersion diagrams and point mobilities of the pipe simulated are compared to those that theoretically obtained. Also the acoustic powers radiated from the pipe are predicted and compared in both cases of air and water as an external medium.

Vibration Analysis for Infinite Length Waveguide Structures Connected with Finite Length Structures Using Impedance Coupling (유한 길이 구조물과 무한 길이 도파관 구조물의 임피던스 연성을 이용한 진동 해석)

  • Ryue, Jungsoo;Lee, Jaehong;Hong, Chinsuk;Shin, Ku-Kyun
    • The Journal of the Acoustical Society of Korea
    • /
    • v.34 no.5
    • /
    • pp.360-370
    • /
    • 2015
  • In case that an infinite length waveguide structure is connected with a finite length structure, it is required to combine a wave approach for the waveguide structure and a modal approach for the finite length structure to investigate the dynamic response of the connected target structure. In this study, the wavenumber finite element (WFE) analysis is adopted for the infinite length waveguide substructure and a finite element (FE) method is applied for the finite length substructure and then their results are coupled in terms of the impedance or mobility at the connected points between the substructures. As a structural model, an infinite length cylindrical shell with a rectangular plate inside is regarded. These two substructures are connected at the four corner points of the plate, rigidly or resiliently. From this investigation, it was confirmed that the wave approach (WFE method) and modal approach (FE method) can be combined by the impedance coupling.

A Study on the Efficient IFEM for Analyzing an Arbitrary-shaped Iris in Rectangular Waveguide (구형 도파관내 임의 형상 Iris 해석을 위한 효율적인 반복 유한 요소법에 관한 연구)

  • 박종국;김병성;남상욱
    • The Journal of Korean Institute of Electromagnetic Engineering and Science
    • /
    • v.12 no.7
    • /
    • pp.1175-1181
    • /
    • 2001
  • An efficient hybrid method is proposed to analyze discontinuities in a rectangular waveguide. Only with a small number of meshes around a discontinuity, the typical finite element method is shown to give an exact solution through several iterative updates of the boundary conditions. To show the validity of the proposed method, a simple circular aperture in a rectangular waveguide is analyzed and its result is compared with FEBIM.

  • PDF

Wave Propagation in a Strip Plate with Longitudinal Stiffeners (보강재를 가진 무한길이 띠 평판의 진동해석)

  • Kim, Hyungjun;Ryue, Jungsoo
    • Transactions of the Korean Society for Noise and Vibration Engineering
    • /
    • v.23 no.6
    • /
    • pp.512-519
    • /
    • 2013
  • It is important to understand the vibrating behavior of plate structures for its many engineering applications. In this study, the vibration characteristics of strip plates that have finite width and infinite length are investigated theoretically and numerically. The waveguide finite element(WFE) approach, which is an effective tool for studying waveguide structures, is used in this study. The WFE method requires only a cross-sectional finite element model, and uses theoretical harmonic solutions to assess wave propagation along the longitudinal direction. First, WFE results for a simple strip plate are compared with the theoretical results(i.e., dispersion diagrams and point mobilities) to validate the numerical model. Then, in the numerical analysis, different numbers of longitudinal stiffeners are included in the plate model to investigate the effects of stiffeners in terms of the dispersion curves and mobilities. Finally, the dispersion curves of a stiffened double plate are obtained to examine the characteristics of its wave propagation.

A Numerical Method for Wave Reflection and Transmission Due to Local Non-Uniformities in Waveguides at High Frequencies (국부적 불연속을 가진 도파관의 고주파수 대역 파동 반사 및 투과 해석 기법)

  • Ryue, Jung-Soo
    • The Journal of the Acoustical Society of Korea
    • /
    • v.29 no.5
    • /
    • pp.314-324
    • /
    • 2010
  • In waveguide structures, waves may be partially reflected by local non-uniformities. The effects of local non-uniformities has been previously investigated by means of a combined spectral element and finite element (SE/FE) method at relatively low frequencies. However, since the SE is formulated based on a beam theory, the SE/FE method is not appropriated for analysis at higher frequencies where complex deformation of the waveguide occurs. So it is necessary to extend this approach for high frequencies. For the wave propagation at higher frequencies, a combined spectral super element and finite element (SSE/FE) method is introduced in this paper. As an example of the application of this method, wave reflection and transmission due to a local defect in a rail are simulated at frequencies between 20kHz and 30kHz. Also numerical errors are evaluated by means of the conservation of the incident power.

Comparison of Absorbing Boundary Conditions and Waveguide Port Boundary Condition for Waveguide Electromagnetic Analysis Using Finite Element Method (유한요소법을 이용한 도파관 전자기 시뮬레이션에 있어 흡수경계조건 및 도파관 포트 경계조건 고찰 및 비교)

  • Mincheol Jo;Woobin Park;Woochan Lee
    • Journal of Internet Computing and Services
    • /
    • v.24 no.2
    • /
    • pp.27-36
    • /
    • 2023
  • Waveguides are transmission lines that guide electromagnetic waves in the desired direction and are utilized in various fields such as medical devices, radar systems, and satellite communications. Computational electromagnetics (CEM) is essential for designing and optimizing waveguides. The finite element method (FEM), which is one of the numerical analysis techniques, is efficient in solving closed problems such as waveguides. In order to apply FEM for waveguide analysis, boundary conditions that truncate the computational domain are required. This paper performs electromagnetic simulations using absorbing boundary conditions (ABC) and waveguide port boundary conditions (WPBC) in 2/D and 3/D waveguides using the finite element method and compared their performances. The accuracy of the analysis was verified by comparing the results with HFSS, a representative commercial electromagnetic simulation software. Simulation results confirm that applying WPBC allows for smaller analysis domains than ABC.

Simulation of Losses in Waveguide Filter using A Commercial CAD Software (상용 CAD프로그램을 이용한 도파관 필터의 손실계산)

  • 이종경;이석곤;안병철
    • Proceedings of the Korea Electromagnetic Engineering Society Conference
    • /
    • 2001.11a
    • /
    • pp.169-171
    • /
    • 2001
  • 본 논문에서는 유한요소법에 기초한 상용프로그램을 이용하여 도파관 필터를 시뮬레이션을 할 경우 도체에 의한 손실을 포함시키는 방법을 제시하였다. 우선 균일한 도파관의 도체에 의한 감쇠의 시뮬레이션 결과를 이론치와 비교하였다. 다음으로 도파관 대역통과 필터의 통과대역 감쇠의 측정결과와 시뮬레이션의 결과를 비교하여 시뮬레이션의 정확도를 검증하였다.

  • PDF

Finite-Element Method Analysis in Eigenmode of Microwave and Optical Waveguides (마이크로파 및 광도파관의 고유모드에 관한 유한요소법 해석)

  • 강길범;윤대일;김정기
    • The Journal of Korean Institute of Communications and Information Sciences
    • /
    • v.14 no.4
    • /
    • pp.321-328
    • /
    • 1989
  • The propagation characteristics of dielectric waveguides has been analyzed by finite element method. We have proposed the finite element formutation of the variational expression in the three-component magnetic field based on Galerkin's method which seek for the propagation constant by a given value of frequency. In this approach, the divergence relation for H is satisfied and spurious modes does not appear and finite element solustions agree with the exact solutions. In order to varify the validity of the present method the numerical results for a rectangular waveguide partilly filled with dielectric are compared with other results.

  • PDF