Sinusoidal Boundary Conditions |
 
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Sinusoidal Boundary Conditions |
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Sinusoidal boundary conditions are used to apply motions which vary sinusoidally with time. They are defined in terms of a node number, degree of freedom, amplitude, phase and period. The last three parameters refer to the sinusoidal function defining the motion. The phase angle is defined relative to the wave datum. If a single regular wave is used in the analysis, the sinusoidal period defaults to the period of the regular wave.
Where structure displacements are specified using the sinusoidal boundary condition option, any other boundary condition may also be applied at the same degree of freedom and at the same node. This can be used, for example, to combine vessel drift (specified via sinusoidal boundary conditions), with high frequency vessel motions (specified using vessel boundary conditions).
This sinusoidal boundary condition option was provided originally for modelling the effect of vessel drift. However more comprehensive and accurate drift modelling capabilities are provided in more recent versions of Flexcom, and these have effectively superseded the sinusoidal boundary condition option. However, they are still retained for compatibility with earlier versions, and you are of course perfectly entitled to use them as required.
•*BOUNDARY is used to define boundary conditions. Specifically, the TYPE=SINUSOIDAL input is used to identify those nodes on the structure whose boundary conditions vary sinusoidally with time.