Example Problem II-8-2 (Continued)

WAVES:

-15.2-m depth MLLW. Events with *H*s>6.1 m were selected for design analysis, a total of 33 cases. The maximum

13.

The data record represented in the table is quite long, and it is considered statistically representative of storm

events to which the site is exposed. It is used as the basis for design. Measured values of *T*p can be taken as

representative of both the gauge and jetty locations. Measured values of *H*s must be transformed between the

gauge location and jetty. Also, the design water level at the jetty must be estimated because it strongly affects

calculations of *H*s.

wave height at the jetty. Refraction between gauge and jetty locations is assumed to be negligible in this example,

and values of *H*0N estimated from gauge data are also applicable to the jetty location. Steps in estimating *H*0N are

listed below and calculation results are given in Table II-8-13. The ACES application "Irregular Wave

Transformation" (Goda's Method) could be used to assist in these and subsequent calculations. It is advisable to

spot-check any ACES calculations with some manual calculations.

(1) Calculate *L*0 from known values of *T*p , *L*0 = (*gT*p2)/(2π) = 1.56*gT*p2 (*L*0 in m).

(2) Calculate *d*gauge/L0 .

(3) Calculate *H*s/L0 as an initial estimate of *H*0N/L0 (needed for using the curves in step (4)).

(4) Get shoaling coefficient *K*s from Figure II-8-22.

(5) Calculate *H*0N from significant height at the gauge *H*sgauge (Table II-8-13) as

(II-9-7)

(6) Calculate *H*0N/L0 to ensure that *K*s from step (4) is valid. It may be necessary to repeat steps (4)-(6)

to arrive at a final value of *H*0N .

Example Problem II-8-2 (Sheet 5 of 21)

Hydrodynamic Analysis and Design Conditions

II-8-39

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