Potential flow round a sharp bend: A comparison between conformal mapping and mode matching

Two-dimensional potential flow along a straight-walled duct with a sharp right-angled bend is considered. This problem is solved using two distinct methods, conformal mapping and matched modal expansions. The main purpose of the paper is to compare the two methods: each gives insight into the other. Applications to genuine waveguide problems are expected, when conformal mapping is no longer available.