Sound energy flux
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| Sound measurements |
|---|
| Sound pressure p |
| Particle velocity v |
| Particle velocity level (SVL) |
| (Sound velocity level) |
| Particle displacement ξ |
| Sound intensity I |
| Sound intensity level (SIL) |
| Sound power Pac |
| Sound power level (SWL) |
| Sound energy density E |
| Sound energy flux q |
| Surface S |
| Acoustic impedance Z |
| Speed of sound c
|
The sound energy q results from the integral particle velocity v of the surface A , whereby only the portions perpendicularly to the surface acoustic velocity are important.
The sound energy flux marks the volume of the transmitting medium (air), which - caused by the excess sound pressure - and flows per time unit (1 s) by a surface A.
The sound energy flux is the average rate of flow of sound energy for one period through any specified area.
In a medium of density ρ for a plane or spherical free wave having a velocity of propagation v, the sound energy flux through the area A corresponding to an effective sound pressure p is
- J = (p2A / ρ v) cos θ
where θ = the angle between the direction of propagation of the sound and the normal to the area A.
