CROSSTEX - Wave Breaking, Boundary Layer Processes, the Resulting Sediment Transport and Beach Profile Evolution
Abstract
Develop phase/depth-resolving numerical models for bottom sediment transport and surf zone hydrodynamics. Validate these models using data measured in CROSSTEX and other field experiments. Identify the role of undertow current, steep waves and breaking wave turbulence on sediment suspension events. Develop simplified phase-resolving formulations for concentrated sediment transport, suspended load transport and its near-bed boundary conditions under breaking waves. A two-phase flow model (Hsu et al 2004; Amoudry et al. 2007) is extended to model sand transport driven by measured random wave-current forcing during CROSSTEX (Scott et al. 2007). Measured near-bed time series of flow velocities are analyzed to extract (approximately) the time series of averaged wave velocities and turbulence quantities (TKE and dissipation rate). These time series are then used to drive the two-phase flow model and to calculate and resulting sand transport from immobile sand bed to the dilute region of about 5 cm above the immobile bed. Physical experiments also provide measured suspended sand concentration in the intermediate to dilute region (volume concentration ~<15%), which can be used to identify the suspension event and to validate the numerical model. On the other hand, two-phase model results for concentrated sediment dynamics can bridge the missing information at the regime of concentration from about 15% to random-close packing (~63%), which is difficult to measure in the physical experiment.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 2007
- Accession Number
- ADA514901
Entities
People
- John H. Trowbridge
- Tian-jian Hsu
Organizations
- Woods Hole Oceanographic Institution