This article is unavailable. Peat, K.S. and Kirby, R. (2000), Acoustic wave motion along a narrow cylindrical duct in the presence of an axial mean flow and temperature gradient, The Journal of the Acoustical Society of America, Vol.107, No.4, pp.1859 -1867 If you wish to obtain a copy please contact the author below: ray.kirby@brunel.ac.uk