Laboratory Study of Steep and Breaking Deep Water Waves

Measurements are presented here of the onset of breaking of deep water waves. The results of recent experiments conducted at NRL to study the growth of steep waves to breaking in a convergent channel are in good agreement with a variety of other recent measurements. For both spilling and plunging breakers, the steepness at breaking Was less than 90% of the computed value for the steepest symmetric wave in deep water. The measured steepness at breaking can be used to estimate the frequency of occurrence of breaking waves in deep water. A discussion also is given of the measured rates of potential energy density and momentum flux losses for spilling and plunging breakers in deep water. The energy density and momentum flux loss rates for a plunging breaker are about twice those measured for a spilling breaker.