Wave Impact on a Wall Using Pressure-Impulse Theory. I: Trapped Air

Abstract

Often when a plunging breaker impacts on a wall, an air pocket is trapped at the wall. This paper extends a pressure-impulse model for wave impact on a wall to include a simple model of a trapped air pocket. The inclusion of an air pocket leads to a higher impulse at impact for a given wave as there is some rebound of the water. The model is shown to compare satisfactorily with small-scale experimental data performed on a caisson breakwater with an impermeable berm. The effect of a porous berm on pressure impulse is investigated theoretically in a companion paper.