Turbulence Structures in the Surf Zone

Turbulence due to breaking waves is an important factor in the ocean as it has a direct effect on coastal erosion, sediment transport and marine life. The laboratory study of this phenomenon is important to produce controlled simulations of processes that occur at sea, and has mainly consisted of temporal point measurements. In this paper the results obtained from using PIV to study the turbulence in the laboratory are presented. PIV is a spatial technique and yields unique information on the turbulence structure in such a flow. Of particular interest in this paper are the evolution of the wavenumber spectra and the form of the turbulent energy decay with time and space. This is used to characterise the decay of turbulence from 2-d to 3-d. Separation of the turbulence from the mean motion is important and the method used here is justified. The main results and conclusions are compared with other research, with similarities and differences emphasised and discussed.