Undular surges interaction with a vertical wall

Abstract

The interaction of nonbreaking and breaking undular surges with a vertical wall is experimentally investigated. The results for nonbreaking undular surges demonstrate that the maximum run-ups agree quantitatively with the predictions of solitary wave theory. During the run-up of a nonbreaking undular surge, the maximum dynamic pressure on a vertical wall occurs at an elevation in the vicinity of the quiescent water level. Both the maximum dynamic pressure and maximum wall force can be accurately estimated from the wave amplitude of the incident surge. By contrast, the breaking surge interactions result in significant amplifications of maximum run-ups and tend to yield extremely high impact pressures at elevations significantly above the still water level. The experimental results indicate the occurrence of extreme impact events for normalized maximum pressures exceeding 1.13. Based on these experimental results, a numerical method is employed to discuss the analogy between a nonbreaking undular surge and a solitary wave. In general, the present results show that the leading front of a nonbreaking undular surge during its initial wave evolution can be satisfactorily described using the solitary wave equation.