HROCEAN, Type, NPHASE
Perform the harmonic ocean wave procedure (HOWP).
TypeSpecifies how to include ocean wave information in a harmonic analysis:
HARMONIC | — | Performs a harmonic analysis using both real and imaginary load vectors calculated via the harmonic ocean wave procedure (HOWP). This behavior is the default. This option performs a harmonic analysis running at a frequency determined by the wave period (specified via OCTABLE command input). |
STATIC | — | Performs a static analysis using both real and imaginary load vectors (calculated via HOWP). This option works by performing a harmonic analysis running at a frequency of 0.0. |
OFF | — | Deactivates a previously activated HOWP and performs a standard harmonic analysis. |
NPHASEPositive number specifying the number of phases to calculate forces. This value must be at least 8. The default value is 20.
The default HROCEAN command (issuing the command with no arguments) is:
HROCEAN,HARMONIC,20
The command applies HOWP when ocean wave information is available (that is, when ocean wave information has been specified via the OCDATA and OCTABLE commands). If this command is issued when no ocean wave information is available, the program generates an error message.
The HROCEAN command applies ocean wave information (obtained via the OCDATA and OCTABLE commands) in a harmonic analysis (ANTYPE,HARMIC) as real and imaginary forces.
You can apply only one ocean load at a time.
The applied frequency in the harmonic (Type = HARMONIC) analysis is based on the wave period input on the OCTABLE command (and not on HARFRQ command
input, which cannot be used). Phase-shift input on the OCTABLE command is ignored.
HOWP does not generate a damping matrix. If you require a damping matrix, you must add it separately.
The command applies to regular wave types only (Airy with one wave component, Wheeler with one wave component, Stokes, and stream function). Irregular wave types are not supported. For information about wave types, see Hydrodynamic Loads in the Mechanical APDL Theory Reference.
The program calculates the forces on each load component of
each element at NPHASE solutions, spread
evenly over one wave cycle. Then, the minimum and maximum, and the
phase between them, are calculated. The command uses the resulting
information to generate the real and imaginary loads.
HOWP cannot be used with stress stiffening.
HOWP works with the full harmonic analysis method (HROPT,FULL) only.
For more information, see Harmonic Ocean Wave Procedure (HOWP) in the Mechanical APDL Theory Reference.
This command is also valid in PREP7.