We found a match
Your institution may have rights to this item. Sign in to continue.
- Title
Evolution of the turbulence structure in the surf and swash zones.
- Authors
In Mei Sou; Cowen, Edwin A.; Liu, Philip L.-F.
- Abstract
The velocity field and turbulence structure within the surf and swash zones forced by a laboratory-generated plunging breaking wave were investigated using a particle image velocimetry measurement technique. Two-dimensional velocity fields in the vertical plane from 200 consecutive monochromatic waves were measured at four crossshore locations, shoreward of the breaker line. The phase-averaged mean flow fields indicate that a shear layer occurs when the uprush of the bore front interacts with the downwash flow. The turbulence characteristics were examined via spectral analysis. The larger-scale turbulence structure is closely associated with the breaking-waveand the bore-generated turbulence in the surf zone; then, the large-scale turbulence energy cascades to smaller scales, as the turbulent kinetic energy (TKE) evolves from the outer surf zone to the swash zone. Smaller-scale energy injection during the latter stage of the downwash phase is associated with the bed-generated turbulence, yielding a -1 slope in the upper inertial range in the spatial spectra. Depth-integrated TKE budget components indicate that a local TKE equilibrium exists during the bore-front phases and the latter stage of the downwash phases in the outer surf zone. The TKE decay resembles the decay of grid turbulence during the latter stage of the uprush and the early stage of the downwash, as the production rate is small because of the absence of strong mean shear during this stage of the wave cycle as well as the relatively short time available for the growth of the bed boundary layer.
- Subjects
TURBULENCE; FLUID dynamic measurements; WAVES (Physics); VELOCIMETRY; SPECTRUM analysis
- Publication
Journal of Fluid Mechanics, 2010, Vol 644, Issue 1, p193
- ISSN
0022-1120
- Publication type
Article
- DOI
10.1017/S0022112009992321