2.5. Impedance of a closed tube using the inhomogeneous wave equation
Boundary conditions
We have already found the impedance of a closed tube by taking the solution to the following Helmholtz wave equation

and applying boundary conditions to the solution. It is known as a homogeneous wave equation because there are no sound sources explicit in the equation. These are included in the boundary conditions that are applied to the solution. Here we shall consider the inhomogeneous wave equation
Get Acoustics: Sound Fields, Transducers and Vibration, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience live online training, plus books, videos, and digital content from nearly 200 publishers.