Wave formation in a high-velocity symmetric impact of metal plates

The impact of metal plates is considered within the framework of the model of a viscous incompressible fluid. The beginning of the wave-formation process in the model is equivalent to the initial stage of origination of instability of a steady flow in Landau’s scenario. To establish the correspondence between the model and the real process, a series of experiments is performed on a symmetric impact of plates made of an aluminum alloy with identical impact angles and different velocities of the contact point. At high values of the Reynolds number and, hence, at high velocities of the contact point, wave excitation is shown to have a soft character; at lower values of Reynolds number, there exists a metastability region where the wave-excitation regime is rather hard; at even lower Reynolds numbers, no action can lead to wave formation, as it follows from the theory. Thus, Landau’s model of origination of instability of a steady fluid flow is found to agree with the process of wave formation in an oblique impact of metal plates.