Acoustic waves propagating in viscous-thermal media include a complex propagating constant in the frequency domain. The attenuation of the acoustic wave is proportional to the shear and bulk viscosity and the thermal conduction coefficient of the media. The interaction between the viscous fluid and rigid walls is taken into account using the Thermo-Viscous BLI Boundary condition.
Analysis Types
The Thermo-Viscous BLI Boundary loading condition is available for Coupled Field Harmonicand Harmonic Acoustics analyses.
Common Characteristics
This section describes the characteristics of the boundary condition, including the application requirements, support limitations, and loading definitions and values.
Dimensional Types
3D Simulation: Supported.
2D Simulation: Not Supported.
Geometry Types: Geometry types supported for the Thermo-Viscous BLI Boundary boundary condition include:
Solid: Supported.
Surface/Shell: Not Supported.
Wire Body/Line Body/Beam: Not Supported.
Topology: The following topology selection options are supported for Thermo-Viscous BLI Boundary.
Body: Not Supported.
Face: Supported.
Edge: Not Supported.
Vertex: Not Supported.
Nodes: Not Supported.
Element Face: Not Supported.
Element: Not Supported.
Loading Data Definition: Not applicable.
Boundary Condition Application
To apply an Thermo-Viscous BLI Boundary:
On the Environment Context tab: select > Thermo-Viscous BLI Boundary. Or, right-click the Environment tree object or click in the Geometry window and select > > Thermo-Viscous BLI Boundary.
Define the Scoping Method.
Details View Properties
The selections available in the Details view are described below.
Category | Fields/Options/Description |
---|---|
Scope |
Scoping Method, options include:
|
Definition |
Type: Read-only field that describes the object - Thermo-Viscous BLI Boundary. Suppressed: Include ( - default) or exclude ( ) the boundary condition. |
Mechanical APDL References and Notes
This boundary condition is applied using the BLI label of SF command. For additional information, see the Boundary Layer Impedance (BLI) Model topic in the Mechanical APDL Acoustic Analysis Guide.
API Reference
See the Thermo-Viscous BLI Boundary section of the ACT API Reference Guide for specific scripting information.