Flexcom > Data Inputs > $LOAD CASE

Purpose

To specify data defining the force terms to be applied to a CALM buoy.

Theory

Refer to CALM Buoy for further information on this feature.

Keyword Format

Three lines defining the calm buoy loads:

Heave Force Amplitude, Heave Force Phase

Surge Force Amplitude, Surge Force Phase

Pitch Force Amplitude, Pitch Force Phase

Table Input

Input:	Description
DOF:	The buoy degree of freedom in which a sinusoidally varying point load will be applied directly in the local axes at the COG node. This column has three pre-defined values that you cannot change. These are ‘Heave’, ‘Surge’ and ‘Pitch’, the significance of which is obvious. For each DOF you specify force RAO and phase values.
Force RAO:	Force RAO for this degree of freedom. See Note (b).
Phase:	Force phase angle relative to the wave at the COG node for this degree of freedom. See Note (b).

Notes

(a)This keyword specifies the force terms to be applied to a calm buoy you defined in the *CALM MODEL keyword. If your Flexcom model includes a CALM buoy, both of these keywords must contain data for the buoy.

(b)The sinusoidally varying point load applied directly in the local axes at the COG node is calculated from the data you input here using the following equation:

where:

•Fi is the force in degree of freedom i

•Aw is the wave amplitude

•Ri is the force RAO for degree of freedom i

•k is the regular wave number (calculated by Flexcom)

•S is the distance of the CoG node from the vertical axis (Y=Z=0) at the start of the dynamic analysis (calculated by Flexcom)

•ω is the regular wave circular period

•t is the current analysis or simulation time

•φi is the force phase angle