Direct measurements (20): Acoustic records
monopole source
dipole source
quadrupole
Acoustic power Pm is proportional to (U: gas velocity)n
Kd = 1/3
(or 0.013)
Km = 1
(sphere)
(1/16 flat circular)
Kq = 3 10-5 - 10-4
+ variation of
external
force (walls of
conduit)
+ variation of
stress
(turbulence)
variation of mass flux
Different types for source of sound:
Km : empirical constant; Rb and Rc: bubble and conduit radius; c: sound
speed