PMLOPT

PMLOPT

PMLOPT, PSYS, Lab, Xminus, Xplus, Yminus, Yplus, Zminus, Zplus, MixOpt
Defines perfectly matched layers (PMLs) or irregular perfectly matched layers (IPML).

PREP7: Artificially Matched Layers

Compatible Products: – | – | – | Enterprise | Ent PP | Ent Solver | –

PSYS

PML element coordinate system number. PSYS may be 0 (global Cartesian) or any previously defined local Cartesian coordinate system number (>10). Defaults to 0. (Not used for IPML.)

Lab

Label defining the number of dimensions (not used for IPML):

ONE	—	A one-dimensional PML region.
THREE	—	A three-dimensional PML region (default).

Xminus

For PML, normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative X direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis.

For IPML, normal reflection coefficient (harmonic analysis); the default value is calculated by the program.

Xplus

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive X direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)

Yminus

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative Y direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)

Yplus

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive Y direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)

Zminus

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in negative Z direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)

Zplus

Normal reflection coefficient (harmonic analysis) or attenuation factor (static structural analysis) in positive Z direction of PSYS. Defaults to 1.E−3 (equivalent to -60 dB) for a harmonic analysis and 30 for a static structural analysis. (Not used for IPML.)

MixOpt

Key for the evanescent wave:

NO	—	Only the propagating wave is attenuated (default). The PML parameter is set to s = 1–jβ.
YES	—	Both the propagating wave and the evanescent wave are attenuated. The PML parameter is set to s = α–jβ (α > 1). The program sets the coefficient α values in terms of the normal reflection coefficients.

Notes

The PMLOPT command can be used to define perfectly matched layers (PML) for acoustic or structural analyses. Each PML region must have a uniquely defined PML element coordinate system (PSYS). Normal reflection coefficient values for a harmonic analysis must be less than 1.

The PMLOPT command can also be used to define irregular perfectly matched layers (IPML) for acoustic analyses. Normal reflection coefficient values for a harmonic analysis must be less than 1.

Issue PMLOPT,STAT to list the current normal reflection coefficient or attenuation factor settings for a PML or IPML region. Issue PMLOPT,CLEAR to clear all normal reflection coefficient settings and restore them to the defaults.

Issue PMLOPT,PSYS,CLEAR to clear all normal reflection coefficient settings for the specified PML element coordinate system and restore them to the defaults.

See Artificially Matched Layers in the Mechanical APDL Acoustic Analysis Guide for more information about using perfectly matched layers (PML) and irregular perfectly matched layers (IPML).

Menu Paths

This command cannot be accessed from a menu.