OMEGA
OMEGA, OMEGX, OMEGY, OMEGZ
Specifies the rotational velocity of the structure.
OMEGX,OMEGY,OMEGZRotational velocity of the structure about the global Cartesian X, Y, and Z axes.
Notes
This command specifies the rotational velocity of the structure about each of the global Cartesian axes (right-hand rule). Rotational velocities may be defined in these analysis types:
Loads for VT and Krylov methods are supported as long as they are not:
complex tabulated loads (constant or trapezoidal loads in tabulated form are supported)
used in conjunction with Rotordynamics (CORIOLIS,on).
In a mode-superposition harmonic or transient analysis, you must apply the load in the modal portion of the analysis. Mechanical APDL calculates a load vector and writes it to the MODE file, which you can apply via the LVSCALE command.
The command supports tabular boundary conditions (%TABNAME_X%,
%TABNAME_Y%, and
%TABNAME_Z%) for
OMEGA_X,
OMEGA_Y, and
OMEGA_Z input values
(*DIM) for full transient and harmonic analyses.
Rotational velocities are combined with the element mass matrices to form a body-force load vector term. Units are radians/time. Related commands are ACEL, CGLOC, CGOMGA, DCGOMG, and DOMEGA.
See Analysis Tools in the Theory Reference for more information.
If you have applied the Coriolis effect (CORIOLIS) using a stationary reference frame, this command takes the gyroscopic damping matrix into account for the elements listed in the Stationary Reference Frame heading in the notes section of the CORIOLIS command. The element axis must pass through the global Cartesian origin. The program verifies that the rotation vector axis is parallel to the axis of the element; if not, the gyroscopic effect is not applied. After issuing OMEGA when the Coriolis or gyroscopic effect is present, a subsequently issued CMOMEGA command has no effect.
The load interpolation setting (KBC) applies
to the rotational velocity, in particular the OMGSQRDKEY
option for quadratic interpolation.
This command is also valid in PREP7.