Physics-Controlled Mesh
When modeling acoustic problems using the Thermoviscous Acoustics, Frequency Domain or the Thermoviscous Acoustics, Transient interfaces the computational mesh can be automatically set up using the Physics-controlled mesh functionality. For these two physics, the generated computational mesh will follow best practices. The mesh will automatically resolve the wave, a boundary layer mesh is added at walls, perfectly matched layer (PML) domains will have an appropriate mapped mesh, and periodic boundaries will be set up with copy mesh operations.
In the Setting’s window for the Physics-Controlled Mesh on the Mesh node in the Model Builder Tree the following controls exist. The Maximum mesh element size control parameter sets the maximum mesh element size. The From physics setting will use the speed of sound and the maximum frequency from the study (frequency domain) or the Maximum frequency to resolve (transient) to set a mesh that resolves the wavelength. The Frequency option lets you enter a specific Maximum frequency to resolve. For both options you can select the Number of mesh elements per wavelength. Finally, the User defined lets you set an actual maximum mesh size. The last option is often the most useful in microacoustic applications, as the wavelength is typically automatically resolved, while it is the geometry that has to be resolved. Use this option to, for example, enter a length scale comparable to a fraction of a narrow waveguide diameter.
If a model contains a Parametric Sweep, the physics-controlled mesh will be regenerated for each new parameter value. This is of course important, if the parameter changes the geometry, the minimum wavelength, or the boundary layer thickness in the model. For example, if a sweep is done over a number of frequency bands, a proper mesh should be regenerated for each band.
In cases where the parameter has no influence on the mesh, remeshing will still take place, and may slow down the solution process. In this case, it is advised to instead use an Auxiliary Sweep (an inner sweep) found in the Study Extensions section.