Particle displacement
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Particle displacement or particle amplitude ξ is a distance measurement in m (metre) of the movement of a particle(real or imagined) in a medium as it transmits a wave. In most cases this is a longitudinal wave of pressure as with sound, but it can also be a transverse wave as with the vibration of a taut string. When applied to a sound wave through a medium of air, particle displacement would be the physical movement back and forth of a molecule of air in the direction the sound wave is travelling as it passes.
It can be represented in terms of other measuements:
- <math>
\xi = \frac{v}{\omega} = \frac{v}{2 \cdot \pi \cdot f} = \frac{p}{Z \cdot \omega} = \frac{p}{Z \cdot 2 \cdot \pi \cdot f} = \frac{a}{\omega^2} = \frac{1}{\omega}\sqrt{\frac{J}{Z}} = \frac{1}{\omega}\sqrt{\frac{E}{\rho}} = \frac{1}{\omega}\sqrt{\frac{P_{ac}}{Z \cdot A}} <math>
- acoustic impedance Z in N·s/m3
- sound particle velocity v in m/s
- frequency f in Hz
- sound pressure p in N/mē = Pa
- angular frequency <math>\omega<math> = 2 · <math>\pi<math> · f
- particle displacement ξ in m
- sound intensity J in W/m2
- sound energy density E or w in W·s/m3
- sound power or acoustic power Pac in W
- area A in m2
Particle amplitude or particle displacement is a very important linear sound field value.
See also
de:Schallauslenkung
