Some Observations of the Behaviour of an Adverse Pressure Gradient Laminar Boundary Layer under Wake Impingement

The problem of laminar to turbulent transition in a boundary layer flow subjected an adverse pressure gradient is relevant many engineering applications. Under such conditions, the initially within can undergo separation and then become upon reattachment, as triggered by instabilities separated shear layer. In turbomachinery blades with high loading, mechanism further complicated presence periodic wake disturbances shed that move relatively upstream flow. paper reports experimental study effect generated on development over flat plate imposed typical highly loaded front-stage compressor blade. Detailed velocity measurements using hotwire are performed along results analysed both time domain frequency domain. Description major features identified provided leading mechanisms trigger process be possible combination amplified Tollmien–Schlichting waves roll-up vortices due Kelvin–Helmholtz instability