Self-organized oblique waves upstream of the leading edge of a flat plate

In this paper, for the first time, we report the formation of self-organized oblique waves upstream of the leading edge of a flat plate. The flow structures are identified by a reflection method and a refraction method via the visualization of water waves. The results show that the interaction of oblique waves leads to the deformation of two-dimensional waves. The oblique waves propagate upstream from the leading edge at all flow velocity cases. As the flow velocity increases, the angle between the oblique waves and the leading edge decreases.