ANSYS AQWA- What's new in version 5.6?

• JONSWAP spectrum for cross-swell seas
• Maximum number of structures and articulations increased to 50 for each
• Improved Green's function integration through Gauss quadrature
• "Lids" for suppression of irregular frequencies and standing waves
• User-defined multi-directional spectra ("carpet" spectra)
• Plotting of added mass and damping for interacting structures
• Full QTF matrix in AQWA-FER
• New Excel to AQWA interface module (AQL)

Cross-Swell Seas

It is now possible to define a JONSWAP or Pierson-Moskowitz spectrum for cross-swell seas.

Increase in number of structures

The number of connected structures and articulations has been increased to 50. The number of diffracting structures remains at 10.

Improved Green's Function

Green's functions are fundamental to diffraction/radiation analysis. In version 5.6 these have been extended to provide more accurate results especially when elements are close to each other or near the water surface.

"Lids" for suppression of irregular frequencies and standing waves

Two "lids" have been introduced for suppression of irregular frequencies and reduction of the standing wave that may occur in a 'moonpool' or between two hydrodynamically interacting vessels. The first release has introduced a manual implementation and it is intended that a future release will implement an automated methodology.

"Carpet" spectra

It is now possible to define a multi-directional spectrum for use in AQWA-LIBRIUM and FER. The input is similar to the present user-defined spectrum except that the spectrum can vary with direction as well as frequency. This allows the user to define, for example:

His/her own spreading function;

A wind driven sea with two separate cross-swells.

A typical plot is shown below.

Plotting of added mass and damping for interacting structures

In the AQWA-GS under Added Mass/Damping Convolution it has been possible to plot the added mass and damping curves for each structure. This facility has been extended to include the curves related to interaction between structures, so now the whole of the coupled added mass and damping matrices can be output graphically.

Full QTF matrix in AQWA-FER

AQWA-FER can now use the full QTF matrix for calculation of drift force spectra.

Interface between AQWA and Excel

A beta version of a new interface between AQWA and Microsoft Excel is included in version 5.6A. It is similar to the popular AXL utility with which users of ASAS will be familiar. This enables results from AQWA analyses to be extracted directly from the backing files into an Excel spreadsheet. The feature provides an effective and efficient tool for user defined report writing as well as enabling further post processing to be performed.