Accession Number : ADA308291

Title :   Time-and Depth-Varying Cross-Shore Currents: Numerical Modeling and Laboratory Measurements.

Descriptive Note : Research rept.,

Corporate Author : DELAWARE UNIV NEWARK CENTER FOR APPLIED COASTAL RESEARCH

Personal Author(s) : Smith, Jane M. ; Svendsen, Ib A.

PDF Url : ADA308291

Report Date : APR 1996

Pagination or Media Count : 222

Abstract : Time and depth varying cross shore currents forced by gravity and infragravity waves in the nearshore are numerically modeled. Model evaluation is made with analytical solutions and laboratory data. Cross shore flow is simulated with two linked models: a depth integrated model and an eigenfunction solution for velocity distribution over depth. Water surface gradients generated by the depth integrated model are used to drive the profile model. Both models are time dependent. Two numerical schemes are used for the depth integrated model, Predictor Corrector and Lax Wendroff. The Predictor Corrector scheme exhibited water surface and velocity oscillations in space when executed with only linear terms. Two disjoint solutions in space were generated. Laboratory data to evaluate the depth integrated and profile models were collected at the SUPERTANK laboratory Project. Wave and current data were collected in a large scale wave channel with a sand beach. The models did not represent mean cross shore currents well due to limitations in the radiation stress calculation. Time varing flows were represented fairly well. Characteristics exhibited by the profile model differed outside and inside the surf zone. Outside the surf zone, most vertical variation in the cross shore current occurs near the water surface, velocities near the surface and bottom are out of phase, and profile variation over depth is fairly symmetric. Inside the surf zone, the mean undertow profile is the dominant feature, time variation of the velocity is fairly constant over depth, and in the inner surf zone, velocity profiles are uniform over depth.

Descriptors :   *OCEAN CURRENTS, *OCEAN MODELS, MATHEMATICAL MODELS, MEASUREMENT, EXPERIMENTAL DATA, COMPUTATIONS, NUMERICAL ANALYSIS, EIGENVECTORS, DEPTH, OSCILLATION, BEACHES, SHORES, SURF, GRAVITY WAVES, CROSS FLOW.

Subject Categories : Physical and Dynamic Oceanography

Distribution Statement : APPROVED FOR PUBLIC RELEASE