The Linearized Potential Flow, Boundary Mode (lpfbm) interface (
), found under the
Acoustics>Aeroacoustics branch (
) when adding a physics interface, is used to compute eigenmodes and out-of-plane wave numbers for the linearized compressible potential flow equations. This study is used, for example, when specifying sources at inlets or analyzing transverse acoustic modes in ducts.
When this physics interface is added, these default nodes are also added to the Model Builder —
Linearized Potential Flow Model,
Sound Hard Boundary (Wall), and
Initial Values. For 2D axisymmetric models an
Axial Symmetry node is also added.
Then, from the Physics toolbar, add other nodes that implement, for example, boundary conditions and sources. You can also right-click
Linearized Potential Flow, Boundary Mode to select physics features from the context menu.
The Label is the default physics interface name.
The Name is used primarily as a scope prefix for variables defined by the physics interface. Refer to such physics interface variables in expressions using the pattern
<name>.<variable_name>. In order to distinguish between variables belonging to different physics interfaces, the
name string must be unique. Only letters, numbers, and underscores (_) are permitted in the
Name field. The first character must be a letter.
The default Name (for the first physics interface in the model) is
lpfbm.
For 2D axisymmetric components, the Azimuthal mode number m (dimensionless) is 0 by default. It is an integer entering the axisymmetric expression for the velocity potential:
The settings are the same as Sound Pressure Level Settings for the Pressure Acoustics, Frequency Domain interface.
This physics interface defines one dependent variable (field), the Velocity potential phi. The name can be changed but the names of fields and dependent variables must be unique within a model.
