Jump to content

Search the Community

Showing results for tags 'voltage source'.



More search options

  • Search By Tags

    Type tags separated by commas.
  • Search By Author

Content Type


Forums

  • Altair Support Forum
    • Welcome to Altair Support Forum
    • Installation , Licensing and Altair One
    • Modeling & Visualisation
    • Solvers & Optimization
    • Multi Body Simulation
    • Conceptual design and Industrial design
    • Model-Based Development
    • Manufacturing Simulation
    • CAE Process Automation
  • Academic Partner Alliance Forum
    • APA - Composites
    • APA - CFD & Thermal
    • APA - Vehicle Dynamics
    • APA - Manufacturing
    • APA - Crash and Safety
    • APA - Noise, Vibration and Harshness
    • APA - System Level Design
    • APA - Structural and Fatigue
    • APA - Marine
    • APA - Optical Design
  • Japanユーザーフォーラム
    • ユーザーフォーラムへようこそ
    • Altair製品の意外な活用例
    • インストール / ライセンス / Altair One / その他
    • モデリング(プリプロセッシング)
    • シミュレーション技術(ソルバー)
    • データ可視化(ポストプロセッシング)
    • モデルベース開発
    • コンセプト設計と工業デザイン
    • 製造シミュレーション
    • CAE プロセスの自動化
    • エンタープライズソリューション
    • データアナリティクス
    • 学生向け無償版(Altair Student Edition)

Categories

There are no results to display.


Find results in...

Find results that contain...


Date Created

  • Start

    End


Last Updated

  • Start

    End


Filter by number of...

Joined

  • Start

    End


Group


AIM


MSN


Website URL


ICQ


Yahoo


Jabber


Skype


Interests


Organization

Found 2 results

  1. This question is frequently asked because three current sources in star connection can lead to convergence problems (and as well three voltage sources in delta connection). This configuration imposes more equations than there are unknowns to find during the solving process. The easiest solution to avoid this issue is to model only two sources instead of three. The voltage or current on the third branch will be imposed by the two others, and the computation will be correct. Flux online help explains it with more details: file:///C:/Altair/Flux_12.2/Help/Flux/english/Website/index.html?SourceDeTensionTriphaseeEnTriangle file:///C:/Altair/Flux_12.2/Help/Flux/english/Website/SourceDeCourantTriphaseEnEtoile.html?key=current sources It is also correct to model the three current sources, but a high resistance must be added in parallel with the 3rd part of the star connection.
  2. Dear Moderator, Consider a half-wavelength strip dipole placed in the origin and oriented along the z-axis with the width along the y-axis. Case 1: Dipole is excited at the (edge-)port with 2V. SWE coefficients up to order n = 10 are requested and exported in an .sph file. Case 2: The structure is removed and the .sph file from case 1 is used as a source and placed in the origin. The equivalent 'virtual' dipole source has the same orientation as the meshed dipole with a voltage source from case 1. Therefore, two problems are equivalent. For a half-wave dipole, FF boundary is set at 2D^2/lambda = 0.5*lambda. Consider the field request in a single point with different radii: (r, theta, phi) = (r, 90, 90) Note that I am always requesting the Near Fields (for radii in both the near-field and the far-field). For FF radii down to approximately 0.7*lambda, both ways yield the same results. For radii between 0.5*lambda and 0.7*lambda, fields obtained in these two ways start to diverge. A numerical example: - > Voltage source: E (0.5*lambda, 90, 90) = - 87.6389 - 86.2589 j. - > SWE source: E (0.5*lambda, 90, 90) = - 87.2327 - 90.8919 j. The difference is large, around 3 in magnitude and 2 degrees in phase. To obtain this value from a set of SWE coefficients, one needs to either expand the field at a particular spherical coordinate using spherical harmonics and Hankel functions, or calculate the far-field first and use the spherical propagation factor exp(-jkr)/r for back-propagation. The former is more accurate for smaller radii. However, even if FEKO used the latter, radii between 0.5*lambda to 0.7*lambda are still in the antenna far-field. Therefore, the calculated fields should be more correct compared to the full-wave voltage source radiated pattern, which I hope we can take as a reference. Furthermore, I compared the results to my own SWE code: - > SWE2: E (0.5*lambda, 90, 90) = - 87.6630 - 86.3141 j, which is much closer to the full-wave result. So my questions are: 1) Why do the results using voltage source and equivalent spherical modes source differ in the 'closer' far-field region? 2) How does FEKO calculate the back-propagation from the SWE source? If the answer is using the exp(-jkr)/r term, would it not be more natural to expand the fields using spherical harmonics and Hankel functions (since you already have the coefficients)? If FEKO does use the harmonic expansion, why does it give the incorrect value for the radii at the FF boundary. The question is important for my research problem so I hope you will be able to answer. Best regards, Tomislav Marinovic (KU Leuven, Belgium)
×
×
  • Create New...