INITIATION OF 3-DIMENSIONAL NONLINEAR TRANSITION PATHS FROM AN INFECTIONAL PROFILE

Strongly nonlinear vortex/wave interaction in a laminar boundary layer as described by Hall & Smith [1991] and Brown et al. [1993] features an algebraic bifurcation, from a zero value of the wave-pressure ampli tude to a non-zero constant value at the initial station of the three- dimensional interaction. In the present study this discontinuity is re moved on a shorter streamwise length scale. On this new scale the wave -pressure amplitude satisfies an integro-differential equation which, depending on the relative signs of the coefficients, possesses a solut ion that matches downstream with the previously-determined constant va lue. There are, however, in addition, further solutions that are of in terest in their own right and which, in conjunction with proposed exte nsions to the equation, indicate the possibility of alternative short or long-scale vortex developments within the boundary layer. These alt ernatives are found more likely to occur than is the strong interactio n described at the start.