2.9 Going further
The class of analogue models based on fluid mechanics is now quite large and the literature is extensive.
Most of the relevant discussion will be deferred until subsequent sections, so for the time being we shall just
mention reasonably immediate generalizations such as:
- Working with specific fluids.
- Bose-Einstein condensates.
- Abstract generalizations.
- Normal modes in generic systems.
- Multiple signal speeds.
We next turn to a brief historical discussion, seeking to place the work of the last decade into its proper