A combined numerical/analytical study of the wide-vortex/wave interaction e
quations, describing boundary-layer instability, is presented. Depending on
the obliqueness beta of the wave input, different solution properties are
obtained. For beta = 1, oscillations in the wave amplitude lead to the evol
ution of a strongly three-dimensional mean flow, while for beta = 2 the int
eraction is characterized by the development of a singularity in the wave p
ressure amplitude. This latter behaviour is modelled using an approximate f
orm for the mean flow skin friction and the resulting amplitude equation is
analysed using a combination of numerical and asymptotic techniques. A sim
ple method is described for determining the singularity location for a give
n spanwise wavenumber, and the asymptotic behaviour of the pressure amplitu
de as the singularity is approached is deduced.