ANSYS Aqwa 16.0 Preview 4 -...

© 2014 ANSYS, Inc. September 19, 2014 1

ANSYS Aqwa 16.0 Preview 4


• Workbench Integration – Aqwa-Librium – Aqwa-Fer

• Workbench Usability – Display Starting Position – Propagate Environmental Data to Linked Systems – Copy/Paste Tree Items

• Diffraction Analysis Enhancements – Solve for Lower Wave Frequencies – Maximum Number of Frequencies Raised – Calculation of Very High and Very Low Frequencies

• High Performance Computing (HPC) – Diffraction – Cable Dynamics

• Miscellaneous – Design Point Updating – Idle Timeout

Summary


Workbench Integration - Aqwa-Librium

• It is now possible to carry out a static equilibrium analysis in Workbench

– At present this is achieved by setting the Computation Type of a Hydrodynamic Response Analysis to “Stability Analysis”

• The dynamic stability capability of Aqwa-Librium is not yet available through Workbench


Workbench Integration - Aqwa-Fer

• It is now possible to carry out a Frequency Domain analysis in Workbench

– At present this is achieved by setting the Computation Type of a Hydrodynamic Response Analysis to “Frequency Statistical Analysis”

• The results available are graphs of RAOs, Response Spectra etc. and tabular output of significant values


Workbench Integration - End-to-End Hydrodynamic Analyses

• Workbench project page showing linked Geometry, Diffraction, Stability, Frequency and Time Response Analyses

– Stability, Time & Frequency Response analyses now conducted using the “Hydrodynamic Response” Analysis System


Workbench Usability - Display Starting Position

• Workbench now shows the system at its equilibrium starting position before the analysis is run

– Previously it was necessary to perform the solution before displaying “Step 1”

Initial geometry

Starting position


Workbench Usability - Propagate Environmental Data to Linked Systems

• It is common for Equilibrium, Frequency and Time Domain analyses to use the same environmental data, which can be time-consuming to set up

– It is now possible to propagate this down from the Equilibrium analysis, ensuring that consistent data is used for each linked analysis


Workbench Usability - Copy/Paste Tree Items

• It is now possible to Copy/Paste and Duplicate tree items, saving time in setting up (e.g.) mooring systems which have several similar cables


Diffraction Analysis Enhancements - Solve for Lower Wave Frequencies

• The Green’s Function database has been extended allowing Aqwa-Line and Hydrodynamic Diffraction in Workbench to solve for lower wave frequencies

• The lower limit depends on the water depth and has been reduced by a factor of 50 from:

0∙05.max{1,√(g/d)} rad/s to

0∙001.max{1,√(g/d)} rad/s

• This will be a benefit in two main areas:

1. In shallow water where it is sometimes necessary to use frequencies below 0.05 rad/s

2. When forward speed causes a low encounter frequency


Diffraction Analysis Enhancements - Maximum Number of Frequencies Raised

• The maximum number of wave frequencies in Aqwa-Line has been doubled from 50 to 100

– This has been a fairly frequent request from customers, and fits well with the increase in speed from parallelization and the reduction in the minimum frequency allowed

– Users can now solve more frequencies over a wider range in less time than in R15.0

Using 50 frequencies Using 100 frequencies


Diffraction Analysis Enhancements - Calculation of Very High and Very Low Frequencies

• Aqwa-Line now automatically calculates the lowest possible wave frequency, in addition to the frequencies specified by the user

– This allows a more accurate calculation of the so-called “5th term” of the QTF coefficients

– The damping at this low frequency is also used to calculate the impulse response function for the convolution of radiation forces

• Aqwa-Line now automatically calculates a very high wave frequency, in addition to the frequencies specified by the user

– This is used as the “infinite frequency” added mass in the radiation force calculation


High Performance Computing (HPC) - Diffraction

• Parallel processing has been implemented for the diffraction calculations in Aqwa

– Works with all ANSYS HPC & ANSYS HPC Parametric Pack options

• Significant speed-up in serial also achieved from further changes to the diffraction solver code

Version & No.

of Cores

R15

Serial

R16.0

Serial

R16.0

2 cores

R16.0

4 cores

R16.0

8 cores

Time (s) 101830 20522 13021 8369 6442

Factor N/A 5.0 7.8 12.2 15.8

Test model with 22276 panels (no. of cores and version varied)


High Performance Computing (HPC) - Cable Dynamics

• Parallel processing has been implemented for the cable dynamics calculations in Aqwa

– Most effective as number of cables elements increases

Test model of a simple box with four cables (no. of cores & cable elements varied)

No. of cable

elements 50 150 250

No. of Cores Time (s) Factor Time (s) Factor Time (s) Factor

1 (Serial) 96.7 1 250.8 1 404.2 1

2 51.7 1.9 128.9 1.9 205.9 2.0

4 27.8 3.5 64.9 3.9 101.0 4.0


Miscellaneous

• Design point updating

– A long-standing defect related to design point updating has been fixed, so users will find it much easier to make practical use of the design point capability in Workbench

• Idle timeout enabled

ANSYS Aqwa 16.0 Preview 4 -...

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