P. Wang et al. / Coastal Engineering 46 (2002) 175211
205
Fig. 24. Sediment-flux profiles obtained from the product of time-averaged profiles of longshore current and sediment concentration.
downdrift traps. The downdrift traps provide accurate
laboratory study, however, do not compare well with
measurement of time- and depth-integrated sediment
the generalized shape derived from the above field
flux across a 0.75-m section of the cross-shore profile.
studies. Profiles at the plunging breaker line are
If the integrated total flux compares well with the
steeper as compared to the generalized shape, while
measured total flux at the traps, this would provide
profiles at the spilling breaker line and in the mid-surf
additional evidence that the product of time-averaged
zone are gentler.
velocity and time-averaged concentration yields rea-
Total sediment flux across a unit width of the surf
sonable estimates of time-averaged longshore sedi-
zone was calculated by integrating the flux profile
ment flux. It is worth noting that sediment flux could
through the water column. This depth-integrated flux
not be calculated within 1 cm from the bed. Because
was compared with the sediment flux measured at the