Acoustic Dipole in a Duct

y

0

0

′

k

5π

2

m

17

view

density

contour

3D

An acoustic dipole oriented along the

x

axis is placed in a duct. The dipole can be moved along the

y

axis. The resulting sonic radiation can be approximated by an

m

-term Fourier series, given in the Details section, with

k'

representing the Helmholtz number (the cut-off frequency of a duct, product of the wavenumber and the duct radius) in multiples of

π/2

.