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Andreas Arapakopoulos

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Posts posted by Andreas Arapakopoulos

  2. Posted · Report reply

    Hi,

    Attached is a revised version of your project with the correct tip geometry. The changes I made involve setting the camber close to the tip region to zero. This adjustment addresses inconsistencies in tip geometry and does not significantly impact performance, as is common practice in propeller design.

    I also included the trailing edge (TE) surface, as required by the NACA geometry used for the curve engine. Given that the engine has an open TE, the blade surface needs to be closed with a TE surface for proper alignment.

    In summary, I followed the propeller sample workflow to ensure accuracy and adherence to design standards.

    Best Regards,
    Andreas

    image.png

    propellerTipRev.cdbc

  3. Posted · Report reply

    Hi,

    Once you've finalized a design in Caeses, you can export the corresponding geometry by following these steps:

    1. Click on the three horizontal lines located in the sidebar.
    2. Next, navigate to the Export option within the Menu workspace.
    3. You'll then encounter various export options for your geometry, including .stl, .step, or .iges file formats.
    4. To specify which geometry you want to export, simply select the desired object in the Object Tree. If no specific object is chosen, the export will default to the visible object in the Object Tree.

    Please refer to the attached figure for clarification on the export process as well.

    Best Regards,
    Andreas
    image.thumb.png.946856def83f33e4ec2a3a1a03ecab8d.png
     

  4. Posted · Report reply

    Hi,

    If you explore the Optimization section of the CAESES documentation, you'll find the answer to your question.

    Below is the content copied from the documentation:

    Colors
    Colors are of interest to check the (linear) correlations. For instance:

    • Blue colors indicate a trend such that if the design variable (abscissa) gets increased, the objective increases as well. The regression curve would go up.
    • Red colors indicate a negative correlation, i.e., if the design variable gets increased, the objective function decreases.

    With this information, you can e.g. check which design variables have no substantial effect on your objective function. These variables could be deactivated in the next optimization stage.

    One additional note: Green colors indicate that the regression curve remains steady.
    So it's a color map that transitions from blue to red, with green as the intermediate color.

    Best Regards,
    Andreas

  6. Posted · Report reply

    Hi,

    Typically, a B-spline curve of a 3rd degree provides sufficient smoothness for engineering applications, with the number of control points being independent of the curve's degree. This configuration allows for localized control over the curve by adjusting individual control point positions.

    In contrast, the number of control points in a Bezier curve is directly tied to the curve's degree. This affords global control over the curve, meaning altering a control point's position affects the curve's shape across its entirety, which may not always be desirable.

    In conclusion, increasing the degree of a curve beyond 9 introduces computational complexity that is unnecessary for practical engineering purposes.

    Best Regards,

    Andreas

  8. Posted · Report reply

    Hi yuvraj,

    I have reviewed the CAESES project and observed that in the "Connection" workspace, the OpenFOAM files are not properly oriented within the directory system, 0, and constant.

    Please refer to the attached photo to understand how a proper integration OpenFOAM with CAESES should be established with the appropriate folder structure.
    Furthermore, you may find a helpful demonstration in an older video from us that illustrates the setup of such an integration: https://www.youtube.com/watch?v=dB9sQxZxqTY
    image.png.0e2625958f31e5703b131d5ff9c0d8fe.thumb.png.f7a7ab78c08430f1939ea530222cc41c.png

    To correct this, you can open the file in CAESES and specify the correct Template Name as seen in the picture below.
    Ensure that these changes are applied consistently across all relevant files.
    image.thumb.png.e254f32880fe57047c73334551c73ec9.png

    Additionally, it's essential to understand the significance of the system, 0, and constant directories in OpenFOAM.
    You can explore the following link for a detailed explanation: https://maplekeylabs.com/understanding-the-openfoam-case-structure/

    Please let me know if implementing these adjustments resolves the issue you were experiencing.

    Best Regards,
    Andreas

  9. Posted · Report reply

    Dear 司思Si Si,

    Please verify in Caeses that the units are correctly set to the appropriate ones.
    For instance, you might have specified units in millimeters, but if the project is set in meters, overlooking this could potentially explain why the model appears to be consistently magnified by a factor of 1,000.

    Best Regards,
    Andreas

    image.png

  12. Posted · Report reply

    Hi Sisi,

    The B-series propeller is currently not available as a sample in CAESES.

    For a design of such a propeller, you can visit our web application at: https://www.wageningen-b-series-propeller.com/
    Additional information about these tools can be found in this post: https://www.caeses.com/news/2018/wageningen-b-series-online-propeller-tool-released/

    Given that the B-series is widely recognized as one of the most comprehensive and commonly used propeller series in marine propulsion, you can also access extensive information in various academic papers.

    Alternatively, you can explore a conventional propeller sample that is not based on the B-series. This allows you to independently examine a typical propeller workflow within CAESES.

    Best Regards,
    Andreas

  14. Posted · Report reply

    Hi Yukai,

    In general, it is always recommended to use the latest version, but I don't believe this is causing any issues. Please carefully compare the input files and geometries in both scenarios.

    Additionally, examine the OpenFOAM log file to identify any differences between the two scenarios. It's possible that while the input geometry remains the same, a distinct mesh is being generated for some reason and this mesh is serving as the input in OpenFOAM.

    Inspect the mesh generator's properties to ensure there are no hidden factors contributing to instability.

    As far as the CAESES setup is concerned, there shouldn't be any significant differences compared to the manual process. The only distinction lies in executing the "Allrun.sh" command from the CAESES GUI rather than directly from the console.


    Best Regards,
    Andreas

  17. Posted · Report reply

    Hi Yukai,

    The force in the last line is the converged value from the solver.

    I would suggest to use a python code only for post-processing.

    For example, if you want to plot the convergence history of the forces over OpenFOAM iterations.

    By parsing various values, such as force in x-axis to parameters and establishing a robust integration CAESES with OpenFOAM, then you can continue with a Design of Experiments and/ or with a Optimization process.

    Best Regards,

    Andreas

    • Upvote 1

  18. Posted · Report reply

    Hi Yukai,


    OpenFOAM is notably complex when it comes to managing numerous processed files. To address this complexity, I've included a screenshot featuring a standard connection input file, geometries, output files, and corresponding values. It's advisable to consistently employ relative paths by utilizing the subfolder option, as illustrated in the second screenshot.

    To extract parameters from the force.dat file, you can directly navigate to the last line, which typically represents the converged value from OpenFOAM. This can be achieved using the -1 option in the command line.

    Moreover, consider incorporating a Python file for post-processing and integrating it into your connection. This can be facilitated by incorporating the Python script as a command line within the Allrun.sh executable file.

    Best Regards,
    Andreas

    image.png

    image.png

    • Upvote 1
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