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SHIPFLOW Connection

SHIPFLOW CFD Analysis​

This introductory tutorial shows how to run the CFD-package SHIPFLOW from within CAESES. In order to keep it simple, an existing IGES geometry is utilized. The CFD settings are configured and a computation gets run finally. The calculation results can be accessed and post-processed, for instance, wave patterns can be visualized in the 3D view.

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Initial Geometry​

The hull needs to be imported first. Instead of using an existing IGES geometry, the subsequent steps do also apply for any parametric model that has been created in CAESES.

  • Download the IGES file of the container vessel we will use for this tutorial

    Download IGES

  • Go to Menu > Import > IGES and import the container vessel.

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Surface Group​

We need to assemble all surfaces in a surface group to have a single object for the upcoming SHIPFLOW configuration.

  • Deselect all curves in the 3DView (1)

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  • Select all surfaces either in the 3D view or in the object tree.

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  • While the surfaces are selected, choose Model > CAD > surfaces > surface based > surface group.

  • The initial default name of the created group is “grp1”. In order to have a more meaningful name, let’s name it “hull”.

Creation of SHIPFLOW Setup​

CAESES provides convenient pre-defined setups for SHIPFLOW for quick and easy configuration:

  • Choose Connect > SHIPFLOW* which creates a configuration and a computation in the tab connections.

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Now, we need to set up the configuration of SHIPFLOW:

  • Expand the object “configigurationShf1” in the tree and select xflow. (1)

  • Choose offset from the pull-down menu of the xflow entry and press the plus-icon next to the pull-down menu. (2)

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  • Select the offset entry and, in the same manner, add iges, lpp, xaxdir, ysign, xori and zori.

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SHIPFLOW Geometry​

The created configuration and its entries can now be filled with project-related values and geometry:

  • Click on the Model tab for access to the geometry (the offset entry is still pinned). (1)

  • Drag and drop the surface group “hull” into the IGES field of the offset entry. (2)

  • Click at the auto-completion icon (“…”) next to the editor field. (3)

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  • Choose exportIGES(FString) from the list and set a name for the geometry file. This command will export all surfaces. (1)

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  • Enter the remaining values according to the screenshot. All additional settings are just defining the coordinate system for SHIPFLOW computations positioned at forward perpendicular backwards orientated.

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SHIPFLOW Main Settings​

SHIPFLOW requires settings for defining the ship type (mono hull), an automatic mesh generation, a free water surface (fsflow) and a coarse mesh, due to computational time reduction. For other computations a coarse mesh might not be efficient enough. CFD speed calculations have to be set as well. Froude and Reynolds numbers are sufficient.

  • Select the hull entry and add ship (“mono”), fsflow and xmdense (“coarse”):

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  • Select the vship entry and add Froude number Fn (0.25) and Reynolds number Rn (1 000 000):

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SHIPFLOW Adding XPAN​

The basic SHIPFLOW settings are ready now. This tutorial will describe a quick potential flow analysis. To set this up, XPAN has to be added with a specified number of iterations and cores available for this computation.

  • Select “configurationShf1” and add xpan to the configuration.

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  • Select xpan and set the maximum number of iterations to 20.

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  • Select the program entry of xflow in the tree and add xpan via the pull-down menu again. This activates the potential flow analysis.

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SHIPFLOW Computation​

The setup is ready now. The last step before running the potential flow analysis is specifying the computation i.e. the object which controls the SHIPFLOW executable.

  • Select the computation “shfComputation1” and add a new local application. (1)

  • Set a meaningful name for the application such as “SHIPFLOW”. (2)

  • Set the path to your file shipflow.bat from the SHIPFLW installation path. (3)

  • Close the editor of the local application so that only “shfComputation1” is given and selected.

Make sure that finally the new local application is chosen from the pull-down menu.

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Run and Monitor SHIPFLOW​

The configuration is ready as well as the computation. Let’s run SHIPFLOW for the given geometry:

  • Select “Run” from the context menu of the computation (1) or from the objectEditor (2).

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The console output of SHIPFLOW can be monitored via the “TaskMonitor” widget which is located at the right-hand side of the user interface.

  • Choose Menu > View > Windows > TaskMonitor (1)

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It shows the singular steps of calculation, such as preparing the offset path, creating offset groups for SHIPFLOW and running 20 iterations of XPAN.

Post-Processing​

CAESES allows post-processing of SHIPFLOW results. Calculation results (several flow and resistance coefficients etc.) are provided as well as interactive visualization of the simulation. Please note that there is a separate tutorial for general post-processing. As a summary, the most important things to know are:

  • The “TableViewer” widget shows the key result values from the analysis. In order to extract a table value, double-click on a single table item: A parameter gets automatically created in the tree (Model) which monitors this value.

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  • The visual results such as wave heights of the potential CFD calculation can be observed in the 3D view.

  • All results can be accessed and configured in the tree of Connect > Post-Processing > Results. In this case, all XPAN data is available in the XPAN scope of “shfComputation1”.

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Final Setup

CAESES Project File​

If you want to take a look at the finalized parametric model you can find the resulting CAESES project file shipflow-connection.cdb here:

Load Final Model