Nonlinear Development of Disturbance in a Laminar Boundary Layer

The nonlinear instability of the disturbances in a boundary layer having a periodic spanwise variation in the thickness was studied by using a multi-channel hot-wire technique and a synchronized sampling method. Measurement of the instantaneous flow field revealed the details of a new type of a nonlinear instability which in the case of a large thickness variation takes place differently from an ordinary two-dimensional boundary-layer case.