Flexcom > User Interface > Model Building > Hydrodynamic Data Importer

This section outlines how the relevant data is obtained from ANSYS Aqwa and converted into Flexcom.

General Data

General parameters such as water depth, water density and acceleration due to gravity located immediately after the "G L O B A L P A R A M E T E R S" tag line, as shown in the following example.

* * * * G L O B A L P A R A M E T E R S * * * *

- - - - - - - - - - - - - - - - -

WATER DEPTH . . . . . . . . . . . . . . . . = 500.0000

DENSITY OF WATER . . . . . . . . . . . . . = 1025.000

ACCELERATION DUE TO GRAVITY . . . . . . . . = 9.806

Hydrostatic Stiffness

The relevant Hydrodynamic Stiffness data is located immediately after the "STIFFNESS MATRIX" tag line, as shown in the following example.

STIFFNESS MATRIX

----------------

X Y Z RX RY RZ

---------------------------------------------------------------------------------

X 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

Y 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

Z 0.0000E+00 0.0000E+00 2.6376E+05 3.0612E-03 -5.5629E-02 0.0000E+00

RX 0.0000E+00 0.0000E+00 3.0612E-03 7.7807E+07 1.2615E-03 3.6241E-02

RY 0.0000E+00 0.0000E+00 -5.5629E-02 1.2615E-03 7.7807E+07 -1.3669E-01

RZ 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00 0.0000E+00

Added Mass and Radiation Damping

The relevant Added Mass and Radiation Damping data is located immediately after the "ADDED MASS" and "DAMPING" tag lines, as shown in the following example.

WAVE PERIOD = 20.000 WAVE FREQUENCY = 0.3142

ADDED MASS

-----------

X Y Z RX RY RZ

---------------------------------------------------------------------------------

X 1.0767E+07 0.0000E+00 -1.3308E+06 0.0000E+00 1.4245E+09 0.0000E+00

Y 0.0000E+00 1.4552E+08 0.0000E+00 3.1150E+08 0.0000E+00 -4.1056E+08

Z -1.1467E+06 0.0000E+00 2.1351E+08 0.0000E+00 -5.7119E+08 0.0000E+00

RX 0.0000E+00 3.0255E+08 0.0000E+00 7.4387E+09 0.0000E+00 -9.1664E+09

RY 1.4697E+09 0.0000E+00 -5.6818E+08 0.0000E+00 6.4888E+11 0.0000E+00

RZ 0.0000E+00 -4.1127E+08 0.0000E+00 -9.4037E+09 0.0000E+00 3.9740E+11

DAMPING

-------

X Y Z RX RY RZ

---------------------------------------------------------------------------------

X 6.9450E+05 0.0000E+00 -1.8941E+05 0.0000E+00 1.5310E+08 0.0000E+00

Y 0.0000E+00 4.3042E+06 0.0000E+00 3.5709E+06 0.0000E+00 -7.8301E+06

Z -7.4658E+04 0.0000E+00 4.1545E+07 0.0000E+00 -1.6408E+08 0.0000E+00

RX 0.0000E+00 3.3832E+06 0.0000E+00 3.1599E+06 0.0000E+00 -2.6940E+07

RY 1.5838E+08 0.0000E+00 -1.5698E+08 0.0000E+00 3.5306E+10 0.0000E+00

RZ 0.0000E+00 -7.8452E+06 0.0000E+00 -2.8377E+07 0.0000E+00 1.0580E+09

displacement RAOs

The relevant Dicplacement RAO data is located after the "R.A.O.S-VARIATION WITH WAVE PERIOD/FREQUENCY" tag line as shown in the following example.

R.A.O.S-VARIATION WITH WAVE PERIOD/FREQUENCY

--------------------------------------------

PERIOD FREQ DIRECTION X Y Z RX RY RZ

------ ----- --------- -----------------------------------------------------------------------------------------------------------

(SECS)(RAD/S)(DEGREES) AMP PHASE AMP PHASE AMP PHASE AMP PHASE AMP PHASE AMP PHASE

----------------------------------------------------------------------------------------------------------------------------------

125.66 0.050 180.00 6.2575 -90.00 0.0000 119.41 1.0047 0.00 0.0000 115.75 0.0945 90.00 0.0146 0.00

51.63 0.122 2.5620 -90.00 0.0000 150.55 1.0304 0.00 0.0000 -8.63 0.2706 90.00 0.0024 -0.06

32.49 0.193 1.6099 -90.00 0.0000 141.59 1.0944 0.00 0.0000 -29.45 0.5835 90.00 0.0009 -0.27

23.70 0.265 1.1956 -90.00 0.0000 127.99 1.2557 0.00 0.0000 -41.72 1.2995 90.00 0.0004 -1.00

18.66 0.337 1.0624 -89.98 0.0000 80.69 1.8408 0.03 0.0001 -55.94 3.7969 90.02 0.0002 -4.17

Force RAOs

The relevant Force RAO data is located immediately after the "FROUDE KRYLOV + DIFFRACTION FORCES-VARIATION WITH WAVE PERIOD/FREQUENCY" tag line, as shown in the following example.

FROUDE KRYLOV + DIFFRACTION FORCES-VARIATION WITH WAVE PERIOD/FREQUENCY

-----------------------------------------------------------------------

PERIOD FREQ DIRECTION X Y Z RX RY RZ

------ ----- --------- -----------------------------------------------------------------------------------------------------------

(SECS) (RAD/S) (DEGREES) AMP PHASE AMP PHASE AMP PHASE AMP PHASE AMP PHASE AMP PHASE

-------------------------------------------------------------------------------------------------------------------------------------

20.00 0.314 0.00 8.55E+06 -91.49 2.63E+00 27.63 4.58E+07 -11.44 1.42E+01 -78.29 1.98E+09 -94.82 3.20E+02 -92.33

17.00 0.370 8.87E+06 -95.13 2.18E+00 -2.05 3.40E+07 -17.49 1.48E+01 51.19 2.08E+09 -96.95 2.94E+01 -108.05

14.00 0.449 6.82E+06 -109.73 2.83E-01 83.66 1.57E+07 -28.48 7.47E+00 43.31 1.83E+09 -105.86 4.27E+02 -93.89

12.00 0.524 3.32E+06 -156.15 3.59E-01 127.59 2.41E+06 -103.73 1.92E+01 -174.22 1.24E+09 -117.83 9.70E+01 -75.68

10.00 0.628 5.28E+06 102.43 8.24E-01 60.76 7.39E+06 148.29 1.03E+01 60.17 1.48E+08 150.79 1.05E+01 0.00

8.00 0.785 3.46E+06 -30.14 6.69E-01 173.29 3.54E+06 -29.80 2.13E+00 -3.37 2.89E+08 36.85 6.40E+01 14.47

6.00 1.047 1.34E+06 10.98 2.68E-01 123.57 8.36E+05 97.85 1.43E+00 -64.00 1.91E+08 54.35 1.18E+01 21.12

QTF data

ANSYS Aqwa provides QTF data in two different forms. The full QTF data includes QTF coefficients for all possible combinations of wave frequency and wave direction, whereas the abbreviated version contains only the diagonal terms of the full QTF matrix. Given that Second-Order Wave Drift Loads in Flexcom are based on Newman's (1974) approximation only, the relevant QTF data is located immediately after the "W A V E - D R I F T L O A D S F O R U N I T W A V E A M P L I T U D E * * 2" tag line, as shown in the following example.

FORCES FREQUENCY DIRECTION (DEGREES)

------ --------- -------------------

DUE TO (RADIANS/SEC) 0.0 20.0 40.0 60.0 80.0 90.0

------ ------------- --------------------------------------------------------

DRIFT

-----

ROLL(RX)

0.314 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.370 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.449 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.524 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.628 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.785 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.047 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.257 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.571 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

2.094 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

PITCH(RY)

0.314 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.370 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.449 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.524 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.628 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

0.785 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.047 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.257 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

1.571 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

2.094 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00

YAW(RZ)

0.314 3.46E-05 -2.35E-03 1.59E-03 -4.15E-04 6.58E-04 -7.53E-05

0.370 1.54E-04 -5.74E-05 -2.93E-03 -4.46E-03 -3.50E-04 -6.78E-04

0.449 -1.03E-05 -2.96E-03 -3.91E-03 9.73E-04 -1.38E-03 1.43E-03

0.524 1.71E-04 -6.45E-03 -3.57E-03 -6.71E-03 -5.78E-03 3.27E-04

0.628 2.02E-03 -5.76E-02 -9.29E-02 -7.14E-02 -3.15E-02 -1.85E-03

0.785 -2.39E-05 1.92E-02 1.40E-02 7.49E-03 4.90E-03 -4.92E-03

1.047 2.80E-04 -1.10E-02 -1.29E-02 -3.02E-02 -8.78E-03 5.78E-04

1.257 1.64E-02 -4.61E-02 -4.92E-02 -9.01E-02 -1.85E-02 1.28E-02

1.571 -7.84E-03 8.18E-02 1.37E-01 1.30E-01 4.57E-02 -6.59E-03

2.094 1.92E-02 -5.31E-01 -3.68E-03 7.27E-01 5.21E-01 -6.05E-04

General Conversions

•The order of translational RAOs is changed from ANSYS Aqwa format (Surge, Sway, Heave) to Flexcom format (Heave, Surge, Sway).

•The order of rotational RAOs is changed from ANSYS Aqwa format (Roll, Pitch, Yaw) to Flexcom format (Yaw, Roll, Pitch).

•The definition of wave heading is transformed such that a zero degree heading, which is incident on the stern in the ANSYS Aqwa format, is incident on the bow in the Flexcom format.

•The units of wave frequency are changed from radians/sec (ANSYS Aqwa format) to Hertz (Flexcom format).

Further Information

Further information may be obtained from the ANSYS Aqwa program documentation which is available via the ANSYS Aqwa website.