Three different files (see Table 1.2: Types of Output Formats and Contents ) could be output, based on your requirement. The format and details of the contents are given in this chapter.
This is an Ansys Neutral file, which contains the following sub-sections:
This section contains the Aqwa2Neut version number, the copyright statement, the hydrodynamic database name (without an extension), the structure sequence number, the date and time when this file was generated, and the phase reference information.
Note: For a structure in a hydrodynamic interaction structure group, the phase is referenced to the center of gravity (COG) of the first structure in that group.
| Data Example | Description |
|---|---|
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Head of section Number of wave periods of the structure specified by Arg2 Wave periods in seconds, up to 10 values per line |
| Data Example | Description |
|---|---|
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Head of section Number of wave directions of the structure specified by Arg2 Wave periods in degrees, up to 10 values per line |
| Data Example | Description |
|---|---|
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Head of section Water depth and density, acceleration due to gravity, structure symmetry indicator |
Note: The structure symmetry indicator here is defined in the following structural hull surface symmetric cases:
=0, no symmetry
=1, port-starboard symmetry
=2, fore-aft symmetry
=3, port-starboard and fore-aft symmetry
This section lists the nodal coordinates of each submerged quadrilateral and triagonal panel, including diffraction panels on the moonpool hull surfaces (if available). The third and fourth nodal coordinates are identical for any triagonal panel.
| Data Example | Description |
|---|---|
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Head of section Total number of submerged panels on whole hull surface Coordinates of four nodes of each panel
(Each element per line) |
| Data Example | Description |
|---|---|
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Head of section Wave period#, direction#, symmetric quadrant#, panel#, pressure amplitude and phase in degrees
(Each element per line) |
Note: The symmetric quadrant# is defined as:
=1, original defined part
=2, fore-aft symmetric mirror part, or port-starboard mirror part if no fore-aft symmetry
=3, port-starboard mirror part for double symmetry
=4, both port-starboard and fore-aft mirror part
The figure above shows the quadrant definition of a structure with both port-starboard and fore-aft symmetries.
| Data Example | Description |
|---|---|
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Head of section Number of tube elements on the structure specified by Arg2 The coordinates of both ends of each tube element
(Each element per line) |
This section starts with the head of WKIN.
| Data Example |
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The hydrodynamic properties at each end of a tube element are listed:
Frequency#, direction#, end# (1 or 2), tube element#, pressure RAO amplitude and its phase in degrees, disturbed wave elevation RAO amplitude and its phase in degrees (on the first line)
Disturbed wave fluid particle velocity component amplitude/unit incident wave amplitude, fluid particle velocity component phase for X-, Y-, and Z-directions respectively (on the second line)
Disturbed wave fluid particle acceleration component amplitude/unit incident wave amplitude and its phase for X-, Y-, and Z-directions respectively (on the third line)
This section starts with the head of RAOs, follows the coordinate of the structure’s COG, then prints out the rigid body RAOs at each wave condition.
| Data Example |
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For each pair of wave frequency and wave direction, the rigid body motion RAOs are listed:
Wave frequency#, wave direction#, translational RAO amplitude and phase in degrees (on the first line)
Rotational RAO amplitude in degrees and phase in degrees for X-, Y-, and Z-axes (on the second line)
This section starts with the head of MASS, follows the coordinate of the structure's COG, and then lists the 6x6 matrix of the structural mass and moment of inertia.
| Data Example |
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This section starts with the head of MASS, follows the coordinate of the structure's COG, then the translational equivalent acceleration RAOs (see Effective Nodal Acceleration RAOs) and the rotational acceleration RAOs of the structure at each wave condition are listed.
| Data Example |
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For each pair of wave frequency and wave direction, the equivalent acceleration RAOs (including equivalent gravity effects) are listed as follows:
Wave frequency#, wave direction#, translational equivalent acceleration RAO amplitude and phase in degrees (on the first line)
Rotational acceleration RAO amplitude in degrees and phase in degrees for X-, Y-, and Z-axes (on the second line)
This is an Aqwa-Wave Neutral file, which contains the following sub-sections:
This section contains the Aqwa2Neut version number, the copyright statement, the hydrodynamic database name (without an extension), the structure sequence number, the date and time when this file was generated, and the phase reference information.
Note: For a structure in a hydrodynamic interaction structure group, the phase is referenced to the center of gravity (COG) of the first structure in that group.
| Data Example | Description |
|---|---|
|
|
Head of section Number of wave periods of the structure specified by Arg2 Wave periods in seconds, up to 10 values per line |
| Data Example | Description |
|---|---|
|
|
Head of section Number of wave directions of the structure specified by Arg2 Wave periods in degrees, up to 10 values per line |
This section lists the nodal coordinates of each submerged quadrilateral and triagonal panel, including the diffraction panels on the moonpool hull surfaces (if available).
| Data Example | Description |
|---|---|
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Note: The third and fourth nodal coordinates are identical for any triagonal panel.
For the indicator of the structure surface post-starboard symmetry:
=0, no symmetry
=1, port-starboard symmetry
For the indicator of the structure surface fore-aft symmetry:
=0, no symmetry
=1, port-starboard symmetry
This section starts with the header of PRES, then follows the pressure data for each submerged hull surface panel.
| Data Example |
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The output data for each panel per line consists of the following:
Wave period in seconds, direction in degrees, symmetric quadrant#, panel#, pressure RAO amplitude and its phase in degrees, including real and imaginary parts of pressure RAO.
Note: The symmetric quadrant# is defined as:
=1, original defined part
=2, fore-aft symmetric mirror part, or port-starboard mirror part if there is no fore-aft symmetry
=3, port-starboard mirror part for double symmetry
=4, both port-starboard and fore-aft mirror part
This section starts with the head of MASS, follows the coordinate of the structure’s COG, and then lists the 6x6 matrix of the structural ass and moment of inertia.
| Data Example |
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This is an Ansys Neutral file, which contains the panel geometric information and the first order hydrodynamic force distribution on the submerged hull surface panels, the submerged tube geometric information and the wave elevations, pressures/velocities/accelerations of submerged sections of the tubes.
The force on the submerged hull surface panel includes the effective gravity force component, which is described in Total First Order Hydrodynamic Force at Panel Centroid in *.ahf File.
This section contains the Aqwa2Neut version number, the copyright statement, the hydrodynamic database name (without an extension), the structure sequence number, the date and time when this file was generated, and the phase reference information.
Note: For a structure in a hydrodynamic interaction structure group, the phase is referenced to the center of gravity (COG) of the first structure in that group.
| Data Example | Description |
|---|---|
|
|
Head of section Number of wave periods of the structure specified by Arg2 Wave periods in seconds, up to 10 values per line |
| Data Example | Description |
|---|---|
|
|
Head of section Number of wave directions of the structure specified by Arg2 Wave periods in degrees, up to 10 values per line |
| Data Example | Description |
|---|---|
|
|
Head of section Water depth and density, acceleration due to gravity, structure symmetry indicator |
Note: The symmetry indicator here is defined in the following structural hull surface symmetric cases:
=0, no symmetry
=1, port-starboard symmetry
=2, fore-aft symmetry
=3, port-starboard and fore-aft symmetry
This section lists the nodal coordinates of each submerged quadrilateral and triagonal panel. The submerged external hull surface panels and the diffraction panels on the moonpool hull surfaces (if available) are included. The third and fourth nodal coordinates are identical for any triagonal panel.
| Data Example | Description |
|---|---|
|
|
Head of section Total number of submerged panels on whole hull surface Coordinates of four nodes of each panel
(Each element per line) |
This section lists the nodal coordinates of each submerged quadrilateral and triagonal panel, including the diffraction panels on the moonpool hull surfaces (if available). The third and fourth nodal coordinates are identical for any triagonal panel.
| Data Example | Description |
|---|---|
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This section starts with the head of FORC, then follows the force data for each submerged hull surface panel.
| Data Example |
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The output data for each panel per line consists of the following:
Wave period#, direction#, symmetric quadrant#, panel#, the first order hydrodynamic force RAO amplitude and phase in degrees in X-, Y-, and Z-direction respectively.
Note: The symmetric quadrant# is defined as:
=1, original defined part
=2, fore-aft symmetric mirror part, or port-starboard mirror part if there is no fore-aft symmetry
=3, port-starboard mirror part for double symmetry
=4, both port-starboard and fore-aft mirror part
| Data Example | Description |
|---|---|
|
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Head of section Number of tube elements on the structure specified by Arg2 The coordinates of both ends of each tube element
(Each element per line) |
This section starts with the head of WKIN.
| Data Example |
|---|
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The hydrodynamic properties at each end of a tube element are as follows:
Frequency#, direction#, end# (1 or 2), tube element#, pressure RAO amplitude and its phase in degrees, disturbed wave elevation RAO amplitude and its phase in degrees (on the first line)
Disturbed wave fluid particle velocity component amplitude/unit incident wave amplitude, fluid particle velocity component phase for X-, Y-, and Z-directions respectively (on the second)
Disturbed wave fluid particle acceleration component amplitude/unit incident wave amplitude and its phase for X-, Y-, and Z-directions respectively (on the third line)
This section starts with the head of RAOS, follows the coordinate of the structure’s COG, and then outputs the RAOs at each wave condition.
| Data Example |
|---|
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For each pair of wave frequency and wave direction, the rigid body motion RAOs are listed:
Wave frequency#, wave direction#, translational RAO component amplitude and phase in degrees (on the first line)
Rotational RAO component amplitude in degrees and phase in degrees for X-, Y-, and Z-axes (on the second line)
This section starts with the head of MASS, then follows the coordinate of the structure’s COG. The 6x6 matrix of the structural ass and moment of inertia is listed.
| Data Example |
|---|
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This section starts with the head of ARAO, follows the coordinate of the structure’s COG, then outputs the acceleration RAOs at each wave condition.
| Data Example |
|---|
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For each pair of wave frequency and wave direction, the rigid body motion acceleration RAOs are listed:
Wave frequency#, wave direction#, translational acceleration RAO amplitude and phase in degrees (on the first line)
Rotational acceleration RAO amplitude in degrees and phase in degrees for X-, Y-, and Z-axes (on the second line)
The error codes may be output when running the program. The error codes and their explanations are listed in Table 1.3: Error Codes and Explanations.
Table 1.3: Error Codes and Explanations
| Error Code | Explanation |
|---|---|
| 1001 | No Aqwa2Neut argument is defined |
| 1002 | Aqwa database file does not exist |
| 1003 | Structure number is less than 1 |
| 1004 | Arg3 is not properly defined |
| 1005 | Arg3 > 5 |
| 1006 | Arg4 is not properly defined |
| 1007 | Failed to read Aqwa model *.dat file |
| 1008 | Failed to create *.xml file |
| 1009 | Failed to read *.res file |
| 1010 | Arg2 (Structure#) is outside the range of structures in the model |
| 1012 | Aqwa database has hydrostatic data only |
| 1013 | Aqwa model has no panel element |
| 1014 | Not valid for forward speed case |
| 1015 | Allocation failed |
| 1016 | Failed to access *.PAC file |
| 1017 | Failed to access *.USS file |