The wide-vortex/Tollmien-Schlichting-wave three-dimensional interactio
n equations are considered in a region of finite adverse pressure grad
ient driving an incompressible boundary-layer flow. The asymptotic str
ucture that emerges enables simplification of the equations and result
s in a partial differential equation governing directly the three-dime
nsional skin-friction field coupled with the effects of the wave forci
ng. The initial linear development of the interaction is described by
an analytic solution and then numerical solutions of the three-dimensi
onal nonlinear interaction equations are presented. The results sugges
t the formation of a finite-distance singularity in the wave pressure
at a location upstream of the point where a Goldstein singularity woul
d occur in the absence of an interaction. A singularity structure is p
roposed which is in agreement with the numerical results and the possi
ble flow development beyond this terminal form is discussed, along wit
h other types of interaction.