RAO Conversion Data Inputs

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RAO Conversion Data Inputs

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rao_conversion

Input

Description

Incident on…:

A drop-down list that allows you to select how the zero degree incident wave heading is oriented relative to the vessel. The default is Bow.

The Custom option allows an arbitrary orientation to be specified. See the ‘RAO – Incident Wave Angle – Specify Dialog’ section for more information.

Specify

Click on this button to display the RAO – Incident Wave Angle – Specify dialog. This button is only available when you select Custom from the Incident on… drop-down list. See the ‘RAO – Incident Wave Angle – Specify Dialog’ section for a detailed description of this dialog.

Mirrored RAOs Required:

A drop-down list that allows you to specify whether or not the RAO values specified in the vessel RAO file are to be mirrored around one or more of the vessel axes. The default is No.

Wave Units:

A drop-down list that allows you to select whether RAOs are specified as a function of wave frequency (either in Hz or rad/s) or wave period (in s) in the vessel RAO file. The default is as a function of wave frequency in Hz.

Heading Units:

A drop-down list that allows you to select whether the incident wave headings specified in the vessel RAO file are given in units of degrees or radians. The default is Degrees.

Phase Angle Units:

A drop-down list that allows you to select whether phase angles specified in the vessel RAO file are given in terms of degrees or radians. The default is Degrees.

RAO Angular Units:

A drop-down list that allows you to select whether the RAO values for the rotational degrees of freedom specified in the vessel RAO file are given in units of degrees (per unit wave elevation) or radians (per unit wave elevation). The default is Degrees.

Response is given as Phase…:

A drop-down list that allows you to select whether phase angles specified in the vessel RAO file define a phase lag or a phase lead relative to the wave elevation. The default is Lagging.

Direction of +ve Angle of Incidence on Plan:

A drop-down list that allows you to select whether positive wave headings (as specified in the vessel RAO file) are measured clockwise or anti-clockwise from the point of zero-degree incident wave heading in a plan view of the vessel. The default is that positive incident wave headings are measured in an anti-clockwise direction.

Wave Elevation:

A drop-down list that allows you to select the sign convention for wave elevations. You may specify whether a positive wave elevation is up or down. The default is that a positive wave elevation is up.

+ve heave direction:

A drop-down list that allows you to select the sign convention for vessel heave. You may specify whether a positive heave represents vessel motion upwards or downwards. The default is that a positive heave represents vessel motion upwards.

+ve yaw relative to +ve heave:

A drop-down list that allows you to select the sign convention for vessel yaw. You may specify whether positive yaw is relative to positive heave in a right-handed or left-handed sense. The default is that positive yaw is relative to positive heave in a right-handed sense.

+ve surge direction:

A drop-down list that allows you to select the sign convention for vessel surge. You may specify whether a positive surge represents vessel motion forward or aft. The default is that a positive surge represents vessel motion forward.

+ve roll relative to +ve surge:

A drop-down list that allows you to select the sign convention for vessel roll. You may specify whether positive roll is relative to positive surge in a right-handed or left-handed sense. The default is that positive roll is relative to positive surge in a right-handed sense.

+ve sway direction:

A drop-down list that allows you to select the sign convention for vessel sway. You may specify whether a positive sway represents vessel motion to port or starboard. The default is that a positive sway represents vessel motion to port.

+ve pitch relative to +ve sway:

A drop-down list that allows you to select the sign convention for vessel pitch. You may specify whether positive pitch is relative to positive sway in a right-handed or left-handed sense. The default is that positive pitch is relative to positive-sway in a right-handed sense.

 

 

RAO – Incident Wave Angle – Specify Dialog

incident_wave_angle_specify

Input

Description

Incident Wave Angle:

The angle between the local vessel surge axis and a wave with zero incident wave heading, measured in degrees anti-clockwise from the bow in a plan view of the vessel. This option is only enabled if you select Custom from the Incident on… drop-down list

Units: [deg]