Starting Conditions - Defaults

The default starting slow position is the position of the structure as originally defined by the user in Data Categories 1 to 4. The default starting slow velocity is zero in all 6 degrees of freedom.

fast position and velocity are not used in a drift frequency analysis. They are assumed to be zero so the total position and velocity are the same as the slow values.

Starting Conditions with the RDEP option

If the RDEP option (Administration and Calculation Options for the Aqwa Suite) is used with a filename given on the RESTART data record (e.g FILE01), then the position in the file FILE01.EQP will override the default slow position. However, if starting positions are defined in Data Category 15 these will in turn override the data in the .EQP file. The default starting slow velocity is zero in all 6 degrees of freedom.

The total position and velocity are the same as the slow values.

POS* or VEL* Specified

The POS* (The POS* Data Record - Starting Positions) and VEL* (The VEL* Data Record - Starting Velocities) data records define the total position and velocity respectively; in a Drift-only analysis they also define the slow position and velocity. The POS* data record will overwrite any values read in from an EQP file.

The POS* and VEL* data records will be over-written by the SLP* and SLV* data records, if they exist.

SLP* or SLV* Specified

The SLP* (The SLP* Data Record - Slow Starting Positions) and SLV* (The SLV* Data Record - Slow Starting Velocities) data records define the slow position and velocity respectively; in a Drift-only analysis they also define the total position and velocity. The SLP* and SLV* data records will overwrite any values read in from an EQP file or from POS* and VEL* data records.

Initial Reactions

It is not possible to specify the initial articulation reactions in Aqwa-Drift. If the positions are correct the articulation reactions will reach equilibrium in the 1st time step.