Published online by Cambridge University Press: 28 March 2006
This paper is concerned with the propagation of a simple wave along a duct of initially constant and then slowly varying cross-section. The equations of motion are linearized in the deviations from the simple wave solution. The solution for the propagation of a centred simple rarefaction wave is obtained in closed form and compared with the results of step-by-step calculations. The results are also found to be good when the area change is not small. Some remarks on boundary-layer influence are included.