202
Coastal Engineering: Theory and Practice
Where Rc is valid in the range 0.03 < Rc/Hs < 3.2. For angled wave
attack, the réduction factor is:
Or = 1 - 0.006/3 for 0° < (3 < 45°
(6.33a)
Or = 0.72 for (3 > 45°
(6.33b)
For impacting waves:
(
/ / p \ \ ~3-24 \
( ( TF ) M
P* (^,3)°‘5
\ \-“S / /
J
(6.34)
Which is valid in the range 0.05 < (Rc/Hs)h* < 1.00. There is no
équivalent expression for different angle wave attack. Besley [1999] also
provides empirical expressions for composite vertical walls fronted by a
mound that may be submerged or emergent.
6.3.3 Complex slopes
The work by Van der Meer [1998] is also considered to be of use for applications that lie outside the range covered by the foregoing methods, for
example assessing overtopping of rather flatter and composite structures. In
some circumstances, this method might be applied to beaches that hâve long
been an unresolved problem. Discussing with the complex slope Fig. 6.7,
the basic expression for the average overtopping rate is given as,
Qm
= 0.06 (tan a)0'5 f^s exp
(Çsfbfffofw)
(6.35)
With a maximum of
Qm
—2.3RC \
(Hsfbff)J
A breaker parameter
is based on the geometry of the structure and
a quasi-wave steepness parameter such that,
Cm = tan a
tan ce =
3HS
QLsiope B)
(6.36)
2tH,J
And fb, ff, f0 and fw are réduction factors for a berm, roughness friction, angle of wave attack and the presence of a vertical wall, respectively.
The berm width is defined as the fiat part of the profile that has a slope
of less than 1:15. The effectiveness of a berm is dépendent on its level in
Coastal Engineering: Theory and Practice
Where Rc is valid in the range 0.03 < Rc/Hs < 3.2. For angled wave
attack, the réduction factor is:
Or = 1 - 0.006/3 for 0° < (3 < 45°
(6.33a)
Or = 0.72 for (3 > 45°
(6.33b)
For impacting waves:
(
/ / p \ \ ~3-24 \
( ( TF ) M
P* (^,3)°‘5
\ \-“S / /
J
(6.34)
Which is valid in the range 0.05 < (Rc/Hs)h* < 1.00. There is no
équivalent expression for different angle wave attack. Besley [1999] also
provides empirical expressions for composite vertical walls fronted by a
mound that may be submerged or emergent.
6.3.3 Complex slopes
The work by Van der Meer [1998] is also considered to be of use for applications that lie outside the range covered by the foregoing methods, for
example assessing overtopping of rather flatter and composite structures. In
some circumstances, this method might be applied to beaches that hâve long
been an unresolved problem. Discussing with the complex slope Fig. 6.7,
the basic expression for the average overtopping rate is given as,
Qm
= 0.06 (tan a)0'5 f^s exp
(Çsfbfffofw)
(6.35)
With a maximum of
Qm
—2.3RC \
(Hsfbff)J
A breaker parameter
is based on the geometry of the structure and
a quasi-wave steepness parameter such that,
Cm = tan a
tan ce =
3HS
QLsiope B)
(6.36)
2tH,J
And fb, ff, f0 and fw are réduction factors for a berm, roughness friction, angle of wave attack and the presence of a vertical wall, respectively.
The berm width is defined as the fiat part of the profile that has a slope
of less than 1:15. The effectiveness of a berm is dépendent on its level in