D.G. Hamilton, B.A. Ebersole r Coastal Engineering 42 (2001) 199218
217
Fig. B2. Irregular wave Test 8E: vertical structure of the mean longshore current at Y27.
point where the measured significant wave height
velocity structure. ADV 6 was located at the position
began to decrease at the highest rate Zsee Fig. 14a..
of incipient wave breaking.
This occurred at the location x s 13.1 m, where
Fig. B2 shows the vertical structure of the mean
the longshore-averaged significant wave height
longshore current for the irregular wave case ZTest
was 0.21 m.
8E.. The mean longshore current in this case is also
Estimates of the position of the mean water line
rather uniform with depth. In the inner surf zone
are x s 2.1 m for the regular wave case and x s 2.4
ZADV 1 through 6., there is a slight increase in
m for the irregular wave case. It should be noted that
current speed with distance from the bed, and the
the cross-shore position of the mean water line could
vertical variations are similar to those measured for
only be estimated with an accuracy of approximately
the regular wave case. In the outer surf zone ZADV 7
"0.1 m. Therefore, the estimates of maximum wave
and 8., the mean velocity is relatively invariant with
set-up are only accurate within "0.003 m.
depth. This trend is different from that in the regular
wave case, where the mean velocity decreased
slightly with increasing distance from the bottom.
Appendix B. Vertical structure of the mean long-
However, in the regular wave case, no waves were
shore current
breaking at ADV 7 and 8; whereas in the irregular
wave case, some wave breaking occurred in this
Fig. B1 shows the cross-shore variation in the
region.
vertical structure of the mean longshore current for
the regular wave case ZTest 6N.. In general, the
mean longshore current is rather uniform with depth.
References
In the inner surf zone ZADV 1 through 5., there is a
slight increase in current speed with distance from
the bed, and outside the surf zone ZADV 7 and 8. a
Brebner, A., Kamphuis, J.W., 1963. Model tests on the relation-
ship between deep-water wave characteristics and longshore
slight decrease in current speed with distance from
currents. Civil Eng. Res. Rep. 31, Queen's University,
the bed. Visser Z1991. measured similar trends in the
Kingston, Ontario, Canada, 28 pp.
vertical velocity structure using regular waves. Pu-
Dalrymple, R.A., Dean, R.G., 1972. The spiral wavemaker for
trevu and Svendsen Z1992. presented a theoretical
littoral drift studies. Proc. 13th Int. Conf. Coastal Eng., Van-
model that predicts similar trends in the vertical
couver, Canada. pp. 689705.
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