Computational investigations have been performed into the behaviour of
an incompressible Newtonian fluid downstream of a plane symmetric cha
nnel expansion in order to determine the critical value of the Reynold
s number, above which the flow becomes asymmetric with respect to the
channel geometry. Two systems have been studied, namely, one in which
the channel walls downstream of the expansion are modelled by the no-s
lip conditions and one in which cyclic boundary conditions are specifi
ed. The two cases are referred to in the present work as the channel a
nd the cascade models, respectively. In both cases, channel systems co
ntaining one, two and three parallel channels which merge via plane, s
ymmetric expansions have been investigated and, where possible, the re
sults have been compared with the experimental and numerical data obta
ined by previous investigators. (C) 1996 Elsevier Science Ltd.