The Linearized Navier-Stokes, Transient (lnst) interface (
), found under the
Acoustics>Aeroacoustics branch (
) when adding a physics interface, is used to compute the acoustic variations in pressure, velocity, and temperature in the presence of any stationary isothermal or nonisothermal background mean-flow. The physics interface is used for aeroacoustic simulations that can be described by the linearized Navier-Stokes equations.
When this physics interface is added, these default nodes are also added to the Model Builder —
Linearized Navier-Stokes Model,
Wall, and
Initial Values. For axisymmetric components, 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 Navier-Stokes, Transient 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
lnst.
Enter the Maximum frequency to resolve in the model. The default frequency is set to
1000[Hz] but should be changed to reflect the frequency content of the sources used in the model. Select the
Time stepping (method) as
Fixed (preferred) the default and recommended or
Free. The
Free option is in general not recommended for wave problems. The generated solver will be adequate in most situations if the computational mesh also resolves the frequency content in the model. Note that any changes made to these settings (after the model is solved the first time) will only be reflected in the solver if
Show Default Solver or
Reset Solver to Defaults is selected in the study.