RT book part
T1 Monitoring of the water particle velocity field near the seabed under different wave and tidal scenarios: a real case
A1 Khan-Mozahedy, A.B.M.
A1 Muñoz Pérez, Juan José
A1 Neves, M. Graça
A2 Física Aplicada
K1 Bottom orbital velocity
K1 tidal current
K1 Shield parameter
AB Monitoring of water particle velocity on the sea bed is crucial to study morphological shore changes in a coast at intermediate and shallow water depth under progressive surface waves and tidal flow current. Therefore, 3-D particle velocity was monitored continuously at the bottom of Santa Maria del Mar (SMM) beach (SW Spain) by means of a single point current meter during 3 weeks in 2007 since August 28. The current meter was placed at 0.45m above the seabed in order to acquire instantaneous velocity. Wave properties (height and period) were taken from the nearby wave buoy and tidal data were taken from a tidal gauge station. Wave-induced bottom particle velocities were obtained during spring and neap tides at a d/L (depth over wave length) parameter ranging from 0.06 to 0.3. Bottom water particle velocity near the seabed ranges from 0 to ± 0.5 m/sec of which about 82% does not exceed 0.2 m/sec during monitoring. Therefore, only 18% of the surveyed water particle velocities exceed the critical Shield parameter of the beach sand (d50 = 0.23mm) which is about 0.05-0.2 depending on Reynolds number. Results show that maximum horizontal speed is obviously lower during the slack tide (high or low tide) in comparison with flood tide and ebb tide. Moreover, speed is higher during ebb tide in comparison to adjacent flood tide, with steady wave climate. Finally and among other conclusions, the maximum real values of the bottom current surveyed in SMM, as well as the Shield parameter, substantially coincide with the theoretical estimates calculated for a given wave and tidal climate.
PB Institute of Water and Flood Management (IWFM)
YR 2015
FD 2015-03-01T00:00:00Z
LK http://hdl.handle.net/10498/17229
UL http://hdl.handle.net/10498/17229
LA eng
DS Repositorio Institucional de la Universidad de Cádiz
RD 13-nov-2026