DEVELOPMENT OF A NUMERICAL BREACH MODEL FORINHOMOGENEOUS SEA-DIKES:PART I. BREACH HYDRODYNAMICS

摘要

The present research is concerned with the development of a numerical model for breaching of inhomogeneous seadikes. In this paper, we mainly address the hydrodynamics of wave overtopping, which is the major hydraulic forcing considered by the present model. A numerical flow module has been developed that is capable of predicting the breach flow on the crest and the inner dike slope under realistically complex hydraulic conditions, i.e. pure wave overtopping or combined wave and surge overtopping. To model breaching properly, besides the average discharge, the capability of simulating individual overtopping events is also of interest. This has been improved in the present model by incorporating effects of energy dissipation of breaking waves through surface rollers in the horizontal momentum equation. Laboratory data from small scale experiments are used for model verification, showing good agreement between the model results and the measurements.