Acoustics is a more direct parallel, and even uses the same unit- the acoustic Ohm. The hydraulic Ohm also exists, but is not really used. Helmholtz resonator

Acoustics is a more direct parallel, and even uses the same unit- the acoustic Ohm. The hydraulic Ohm also exists, but is not really used. Helmholtz resonators[1] are used to provide capacitive acoustic impedance in a gas system. Archetypically a beautiful hollow copper sphere. Ported subwoofers use the same formulas, as do some types of automotive exhaust. Exhausts use a long pipe and cylindrical section to form a low-pass filter, which transforms the individual exhaust bursts of an engine into a smooth continuous flow. Two stroke exhausts[2] are band-pass filters that improve compression by putting backpressure on the engine at the correct time. [1]: https://en.wikipedia.org/wiki/Helmholtz_resonance https://en.wikipedia.org/wiki/Helmholtz_resonance [2]: https://en.wikipedia.org/wiki/Expansion_chamber#/media/File:Scooter_exhaust.jpg https://en.wikipedia.org/wiki/Expansion_chamber#/media/File:...