At least six elements per wavelength should be used with higher-order acoustic elements (FLUID220, FLUID221). Buffer and PML regions should have more than four elements between the boundaries.

If a large frequency range is solved, the lowest frequency solved has a large wavelength and the highest frequency solved has a small wavelength. To solve for a large frequency range and satisfy the two requirements stated above, it may be necessary to use very large PML and buffer regions (to address low frequency requirements) meshed with very small elements (to satisfy high frequency requirements). This can be computationally expensive.

Because the element size depends on wavelength, acoustic analyses benefit greatly from parametric models where each frequency is solved with a mesh that is optimal for that configuration. Parametric models can be generated using the APDL command language, or they can be generated within Ansys Workbench using Ansys DesignModeler and Workbench Mechanical.

With supported graphics cards, GPU Accelerator can speed up solutions when used with the sparse direct solver. A run of this example problem is tabulated below with total elapsed time normalized to the baseline case of a single core without GPU Accelerator.

In this case, use of GPU Accelerator resulted in a solution time 1.76 times faster for two cores using this particular hardware configuration.