HR: 14:20h
AN: OS33C-02    [Abstracts]
TI: Three Dimensional Flow Dynamics Over A Hollow
AU: * Salas-monreal, D
EM: davsalas@uv.mx
AF: Centro de Ecologia y Pesquerias, Univerisdad Veracruzana, Hidalgo 617 Col. Rio Jamapa, Boca del Rio, VER 94290, Mexico
AU: Valle-Levinson, A
EM: arnoldo@ufl.edu
AF: Department of Civil and Coastal Engineering, University of Florida, PO Box 116580 32611-6580 Gainesville , Gainesville, FL 32611-6580, United States
AB: Current velocity and water density profiles were measured in order to observe the effects of bathymetric depressions (hollows) on a continuously stratified flow. Data were obtained in February 2000, November 2001 and May 2002 over two hollows in the lower Chesapeake Bay. Measurements showed an acceleration of the mid- depth flow as it moved toward the deepest part of the hollow, in contrast to the deceleration expected from two- dimensional Bernoulli-type dynamics. The acceleration was attributed to lateral water intrusions that were most apparent during floods. The development of lateral water intrusions was corroborated by observations in a transverse section that crossed the deepest part of one of the hollows. The current acceleration toward the deepest part of the hollows during flood, favored by lateral water intrusions, was deflected toward the right (looking landward) owing to Coriolis accelerations. In general during ebb and flood, the dynamics over the hollows could be explained with three-dimensional Bernoulli-type dynamics (pressure gradient balanced by advection) modified by Coriolis acceleration. Outside the hollows the dynamics should be between pressure gradient and friction. The transition from frictionally dominated dynamics (outside the hollow) to advectively dominated (inside the hollow) appears at the region where the bathymetric slope equals the bottom drag coefficient. The development of lee waves with periodicities of 1.42 h was evident during flood and ebb tide periods, produced by the interaction of the increasing bottom slope and the stratified flow.
DE: 4512 Currents
DE: 4546 Nearshore processes
DE: 4558 Sediment transport (1862)
DE: 4560 Surface waves and tides (1222)
SC: Ocean Sciences [OS]
MN: 2007 Joint Assembly