EM 1110-2-1100 (Part II)
30 Apr 02
Example Problem II-8-2 (Continued)
Table II-8-21
Calculation of Hstoe for Storm Event 11 at Jetty Head
djetty (m)
10.0
djetty/H0'
1.63
Hsjetty/H0'
0.95
Hsjetty (cm)
582
1
H0'=613 cm; H0'/L0=0.0216
Figure II-8-30.
Return period wave heights, toe design, jetty head
Effect of currents on waves. Information on currents around the jetty head is not precise but indicates that strong
currents of up to 3 m/s may be experienced during design storms. The currents must be considered in design for
two reasons: 1) direct impact on bottom and jetty material stability; and 2) effect on waves. Part II-6-2.l provides
a simple method for estimating a factor for wave height modification by currents RH. The following
nondimensional parameters are required:
V cos θ
F '
gd
(II-8-8)
d 1/2
2π
Ω '
T
g
where V is the current speed and θ is the angle between the current and a wave orthogonal. For this design
problem, V= 3 m/s and θ is taken as -180 deg (current directly opposing the waves).
Example Problem II-8-2 (Sheet 18 of 21)
II-8-52
Hydrodynamic Analysis and Design Conditions
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