The Dynamics of Cobbles In and Near the Surf Zone and Mine Movements In and Near the Surf Zone
Abstract
GOAL. The long-range goals of this research are to develop, by laboratory experimentation, theoretical analyses and comparisons with field experiments, a basic understanding and, eventually, a predictive capability of the motion of cobbles in the shoaling, wave-breaking and swash zones (here, the size classification of cobbles used by the American Geophysical Union as particles in the diameter range 6.4 to 25.6 cm is employed). OBJECTIVES The scientific objectives established for the next several years are directed toward better understanding the motion of cobbles on sloping beaches which (a) are impermeable (with various characteristic roughnesses) and (b) are permeable with bedforms that are free to vary with time. The objectives for the impermeable floor case are to: (i) develop proper parameterizations for the background velocity field in the shoaling, wave-breaking and swash zones; (ii) obtain data on the drag, lift and friction forces acting on a cobble which is subjected to the action of a periodic shear flow with simultaneous onshore and offshore velocities at certain phases of the motion and having layer thicknesses comparable to the thickness of the cobbles (as in the swash zone) and, similarly, for a periodic flow for which the fluid depth is much greater than the thickness of the cobbles (as in the shoaling and wave-breaking zones); (iii) use of the parameterizations obtained in (i) and (ii) to extend the models previously developed for simplified time-dependent flows to include the entire space- and time-dependent surf zone; (iv) obtain data on the transport of cobbles in the entire wave-tank surf zone for a broad range of external parameters (size, shape, density and friction coefficient of cobbles, amplitude and frequency of waves and water depth); and, (v) test the analytical/numerical model against the experimental data and to adjust the model as appropriate. The objectives for the permeable slope case are directed to better understanding the detail
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 30, 1997
- Accession Number
- ADA635161
Entities
People
- Don L. Boyer
- Harindra Fernando
- William N. Houston
Organizations
- Arizona State University