*FPF

Data format:

One line with 7 parameters, followed by an arbitrary number of lines comprising 13 values each, as follows:

ITOP GTOP(1) GTOP(2) GTOP(3) YAWF ENCASD PSID
PERIOD(1) ASURG(1) FISURG(1) ASWAY(1) FISWAY(1) AHEAV(1) FIHEAV(1) AROLL(1) FIROLL(1) APITCH(1) FIPITCH(1) AYAW(1) FIYAW(1)
...
PERIOD(N) ASURG(N) FISURG(N) ASWAY(N) FISWAY(N) AHEAV(N) FIHEAV(N) AROLL(N) FIROLL(N) APITCH(N) FIPITCH(N) AYAW(N) FIYAW(N)

Status:

Optional (time-domain dynamic analyses).

Purpose:

To define the position of the floating vessel ( Floating Production Facility) and its motion RAO.

Restriction:

Keyword WAVE or WAVJON is required.

Details:

Parameter	Description
ITOP	Number of the node attached to the FPF
GTOP(1)	X-component of the vector GT, from the FPF centre of motion to the top riser, in the FPF REFERENCE
GTOP(2)	Y-component of the vector GT, from the FPF centre of motion to the top riser, in the FPF REFERENCE
GTOP(3)	Z-component of the vector GT, from the FPF centre of motion to the top riser, in the FPF REFERENCE
YAWF	angle between the Ox axis of the global reference and the FPF surge axis (degrees)
ENCASD	built-in angle /Oz(degrees)
PSID	built-in angle /Ox(degrees)
PERIOD(I)	periods at which the FPF transfer function is defined
ASURG(I)	Ratios of the amplitude of the FPF motion for surge at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FISURG(I)	Motion RAO phase (degrees) for surge at the correspnding PERIOD(I)
ASWAY(I)	Ratios of the amplitude of the FPF motion for sway at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FISWAY(I)	Motion RAO phase (degrees) for sway at the correspnding PERIOD(I)
AHEAV(I)	Ratios of the amplitude of the FPF motion for heave at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FIHEAV(I)	Motion RAO phase (degrees) for heave at the correspnding PERIOD(I)
AROLL(I)	Ratios of the amplitude of the FPF motion for roll at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FIROLL(I)	Motion RAO phase (degrees) for roll at the correspnding PERIOD(I)
APITCH(I)	Ratios of the amplitude of the FPF motion for pitch at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FIPITCH(I)	Motion RAO phase (degrees) for pitch at the correspnding PERIOD(I)
AYAW(I)	Ratios of the amplitude of the FPF motion for yaw at the corresponding PERIOD(I), to the amplitudes of the corresponding wave.
FIYAW(I)	Motion RAO phase (degrees) for yaw at the correspnding PERIOD(I)

Note

1) The motion of the FPF with respect to the wave is defined as follows

$$ Xxx = WAVAMP * Axx * \cos(\frac{2\pi t}{PERIOD} + PHIxx) $$

with :

$$ PHIxx = \frac{\pi}{180} * (FIxx + PHASExx) - Kxx * (X_{\alpha} \cos TETH + Y_{\alpha} \sin TETH) $$

where $PHASExx$ is the phase at the origin of wave $xx$, $TETH$ is the angle between the X-axis and the incident wave $Kxx$, $(XG,YG,ZG)$ are the co-ordinates of the vector $\vec{OG}$, $Kxx$ is the wave number.

2) If keyword WAVJON is used, PERIOD(1) must be less than TP/2.5 and PERIOD(n) more than 2TP. If the spectrum is out of these bounds, the program will stop. In case the program stops, search for the word R.A.O. in the .LIS file to have some information.

3) ENCASD is usually negative.

Example:

  *FPF
  c node   x     y     z    angle  encasd   psid
      1   -30.6  0.  10.0    180.   -5.76      0.
  c period  < surge >  < sway >  < heave >  < roll >  <  pitch  >  < yaw.>
  10.3      .006 54.9   .0   0.  .25  98.4   0.  0.    .55  -99.   0.  0.

This example corresponds to a regular wave with a period of 10.3 s. The top riser is at the rear of the vessel, at 30.6 m from the centre of motion G, on the centreline GX, 10 m above the mean sea level. The vessel is directed toward the -X direction and the built-in angle with respect to the vertical axis is -5.76 degrees.

*FPF

  c node  x    y   z     angle encasd   psid
  1     -36.7  0.  14.4  180.
  c  period   < surge >  < sway >  <  heave >  < roll >  <  pitch  >  < yaw.>

  5.000  .04  0.  0.  0.  .00  0.  0.  0.  .01  60.  0.  0. 
  5.625  .09  60.  0.  0.  .00  240.  0.  0.  .01  -60.  0.  0. 
  6.250  .15  90.  0.  0.  .00  180.  0.  0.  .02  -90.  0.  0. 
  6.875  .19  90.  0.  0.  .00  180.  0.  0.  .07  -90.  0.  0. 
  7.500  .15  90.  0.  0.  .00  120.  0.  0.  .15  -90.  0.  0. 
  8.750  .04  -150.  0.  0.  .11  0.  0.  0.  .27  -90.  0.  0. 
  10.000  .15  -90.  0.  0.  .22  0.  0.  0.  .38  -90.  0.  0. 
  11.250  .31  -90.  0.  0.  .32  0.  0.  0.  .41  -90.  0.  0. 
  12.500  .43  -90.  0.  0.  .39  0.  0.  0.  .40  -90.  0.  0. 
  15.000  .60  -90.  0.  0.  .47  0.  0.  0.  .36  -90.  0.  0. 
  17.500  .71  -90.  0.  0.  .51  0.  0.  0.  .29  -90.  0.  0. 
  18.750  .75  -90.  0.  0.  .45  0.  0.  0.  .23  -90.  0.  0. 
  20.000  .80  -90.  0.  0.  .39  0.  0.  0.  .22  -90.  0.  0. 
  21.875  .83  -90.  0.  0.  .13  150.  0.  0.  .19  -90.  0.  0. 
  22.500  .84  -90.  0.  0.  .50  180.  0.  0.  .18  -90.  0.  0. 
  23.750  .86  -90.  0.  0.  1.20  -90.  0.  0.  .15  -90.  0.  0. 
  24.375  .88  -90.  0.  0.  1.50  0.  0.  0.  .14  -90.  0.  0. 
  25.000  .90  -90.  0.  0.  1.35  0.  0.  0.  .13  -90.  0.  0. 
  26.000  .00  0.  0.  0.  .00  0.  0.  0.  .0  0.  0.  0. 
  29.000  .00  0.  0.  0.  .00  0.  0.  0.  .0  0.  0.  0.

This example corresponds to an irregular wave previously defined by *WAVJON. The last two periods were added to include the whole spectrum. The values used here are not very important since they correspond to frequencies with very little energy.