Microacoustics: Acoustics in small Devices with Thermoviscous Losses
When devices have geometric details comparable to the thermal and viscous boundary layers thermoviscous losses start to become important. This typically occurs in the millimeter and sub millimeter range in air, hence the name: Microacoustics.
- What is the influence of the thermoviscous losses on the performance of a device?
- How large are the losses?
- Can the losses be used for improved sound control?
These questions can be answered using simulation. Typical areas of application include loudspeakers, microspeakers, hearing aids, MEMS components, microphones, perforates, meshes and many other. In traditional loudspeakers thermoviscous losses can play a role in small gaps (like in the air gap between coil and pole piece) or in the acoustic behavior of screens and mesh. Yet another example is that of a compression driver, where including the losses in the phase plug is essential to get the correct acoustic predictions.
Image from COMSOL