抄録
This paper describes an experimental investigating of natural transition mechanism of a wake forming behind a thin aerofoil in a towing wind tunnel. A linear stability analysis shows that an absolute instability pocket occurs downstream of the aerofoil trailing-edge. In the process of natural transition, the slight disturbances existing in the flow grow up selectively, and create the structures of vortex street in the wake. When the aerofoil is towed in the tunnel, starting vortices are generated in the wake. The experimental result shows that the feature of starting vortex affects the natural transition process due to the existence of absolute unstable region.
