The evolution and runup of nonbreaking undular surges

Physical experiments were conducted in a long water wave tank over a wide range of still water depths to study the evolution and runup of nonbreaking undular surges generated by the release of a given volume of water. The results demonstrated that the wavefront of a nonbreaking undular surge closely matched that of the corresponding solitary wave of the same height. The wave celerity of the surge could be accurately predicted using the solitary wave theory. Two distinct wave stages existed in the evolution process of a nonbreaking undular surge based on the wave shape asymmetry. The wave stage transition could be approximated as a surge Froude number equal to 1.15. The wave amplitude and steepness of undular surges were in reasonable agreement with the linear wave theory for surge Froude numbers greater than 1.20. However, the wave length data presented a different pattern to that predicted by either the linear wave theory or the solution of the Boussinesq equation. Furthermore, the maximum surge runup on a vertical wall was in excellent agreement with the solitary wave theory. This study provided new insights into the quantitative behavior of nonbreaking undular surges.