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Waves plunging breakers

Experiments show that berm width designed according to Eq. (22.16) is also able to protect the sand bed against the breaker-induced scour at the inshore side of the head. However, scour might occur in the protection layer itself due to wave plunging. Therefore, over-sizing of the protection material is recommended at the inshore side compared to the usual rule provided, for instance, by formula (22.17), van der Meer et... [Pg.626]

Figure 5.7 shows the time series of bubble diameter distribution just beneath the mean water level near the breaking point under the same wave condition as in Fig. 5.5. The bubble diameter here means the averaged value of the major and minor diameter. The horizontal axis is the characteristic bubble diameter, the vertical axis is the temporal change, and the contour indicates number of bubbles per unit area. The plunging wave breaking not only entrains the bulk of air but also generates a large number of bubbles in comparison with the spilling breaker. As discussed earlier, the void fraction decreases exponentially in time. The time series... Figure 5.7 shows the time series of bubble diameter distribution just beneath the mean water level near the breaking point under the same wave condition as in Fig. 5.5. The bubble diameter here means the averaged value of the major and minor diameter. The horizontal axis is the characteristic bubble diameter, the vertical axis is the temporal change, and the contour indicates number of bubbles per unit area. The plunging wave breaking not only entrains the bulk of air but also generates a large number of bubbles in comparison with the spilling breaker. As discussed earlier, the void fraction decreases exponentially in time. The time series...
Figure 28.4 shows the computed cross-shore variations of Figure 28.4 shows the computed cross-shore variations of <lsx, fmd q for the spilling and plunging wave tests. The cross-shore bedload transport rate q x is positive (onshore), whereas the cross-shore suspended sand transport rate qsx is negative (offshore). The absolute values of q x and q x are larger in the breaker zone near a = 4 m and near the stiU water shoreline, especially for the plunging waves. The computed total sand transport rate q = [qbx+qsx) is positive (onshore) except in the zone near the shorehne where qx < 0. The absolute value of qx is less than about 0.05cm /s but = 0 is required on the equilibrium beach. Consequently, the profile evolution is computed using the measured quasi-equilibrium profile as the initial profile. The initial profile is exposed to the wave conditions listed in Table 28.1 for 10 horns. The computed profile is shown in Fig. 28.3. The computed change of the bottom elevation Zb is less than about 5 cm. The subtle profile change is difficult to predict and measme accurately. It is noted that the fluid velocity and suspended sand concentration were not measured synchronously in these tests, resulting in no measmement of qsx ...
See other pages where Waves plunging breakers is mentioned: [Pg.137]    [Pg.139]    [Pg.457]    [Pg.622]    [Pg.624]    [Pg.88]    [Pg.386]    [Pg.458]   
See also in sourсe #XX -- [ Pg.137 , Pg.139 ]



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