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Damping data

In this tab a damping file can be imported and options can be chosen which are related to hydrodynamic damping properties. 


The following checkboxes can be checked:

  • Scale damping file
  • Wichers damping
  • Use Aranha approximation


Scale damping data

When a damping file is available this damping data can be scaled with the scale factor from the Ship data tab. This is done when the check box "Scale damping file" is selected. A damping file contains linear and quadratic damping coefficients for six degrees of freedom. These damping coefficients can be the results of decay tests, for example. Here is an example showing linear damping for surge, sway, roll and yaw.
Using a damping file is not obligatory. The file can be imported, exported or deleted. Importing a file means that a file is zipped into the aNyMoor input file (<name>.any). Exporting means that a file is extracted from the aNyMoor input file and a local copy is made, so that the contents of the file can be viewed. Deleting a file means that a file is removed from the aNyMoor input file.

The file should contain two columns, separated by spaces and/or tabs. The first column contains linear damping coefficients for all 6 degrees of freedom, the second column contains quadratic damping coefficients. The units of the linear damping coefficients are [kN/m/s] and [kNm/rad/s], the units of the quadratic coefficients are [kN/(m/s)2] and [kNm/(rad/s)2].


Wichers damping

The so-called Wichers damping is applied. This is a calculation method for viscous damping, with and without current, for tanker shaped vessels. More information can be found here in section 4 or here.


Use Aranha approximation

The Aranha method is applied for the correction of wave drift forces due to current. It has two additional properties to set:

    1. Use Aranha without taking current into account
    2. Use Aranha using the Newman correction on the P-matrix


More information can be found here.

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