TM 5-850-1
H = 0.026U2
explosion-generated waves is extremely localized when
5-8)
compared with the several-hundred-mile-wide area
where U represents wind velocity in knots.
(e) When the maximum wind velocity, as well as
affected by a tsunami.
The periods of nuclear-
explosion-generated waves can roughly be classified as
the fetch, is known, a more accurate determination of the
being between that of wind waves and tsunami waves,
design wave is possible using figures 5-2 through 5-13.
i.e., they are in the long-period wave region but can
(2) For final design of structures of major
have amplitudes considerably greater than those of
importance. For such design or where the extent of the
normal long-period waves found in the open ocean.
d. Design wave calculation.
development warrants more accurate determination of the
(1) For preliminary study and/or structures
wave characteristics, follow the procedures given below:
where occasional damage may be permissible. One of
(a) Make an analysis of a comprehensive series
the following procedures may be used:
(a) Refer to local records and experiences
of aerial photographs of the incident waves generated by
of longtime residents.
severe storms.
(b) Hindcast (i.e., calculate from historic,
(b) Make observations at the site of such
physical features as wash and runup marks and debris.
synoptic weather charts) the characteristics of waves
(c) Use the following empirical relations
resulting from several of the more recurrent deepwater
for open seas and inland lakes.
storms. Determine the shallow-water characteristics of
these waves by use of refraction and diffraction diagrams.
Open seas (Stevenson formula)
The determination of the characteristics of the incident
waves by hindcasting is the most reliable method for
H = 1.5 F for F> 30 nautical miles
(5-4)
determining the design wave. Detailed wave and water
or
level predictions are given in "Shore Protection Manual,"
H = 1.5 F + 2.5 -
F for F< 30
4
Vol. 1. (See app A.)
e. Wave pressure on vertical walls.
nautical miles
(5-5)
Wave
pressures due to breaking and nonbreaking waves differ
Inland lakes (Molitor formula)
widely. The first step in the evaluation of wave forces is to
determine if the structure will be subjected to forces from
nonbreaking waves, breaking waves, or broken waves.
H = 01.17 UF For F > 20 nautical miles
(5-6)
The determination of wave pressure on vertical walls is
or
explained in "Shore Protection Manual," Vol.
H = 0.17 UF + 2.5 -
F for F < 20
4
II. (See app A.)
f. Wave forces and movements on piles. Waves
nautical miles
(5-7)
acting on piles exert pressures that are the result of drag
where
and inertial forces. The determination of waves forces and
H = wave height, feet
movements on piles can be found in "Shore Protection
F = fetch, nautical miles
Manual," Vol. II. (See app A.)
U = maximum wind velocity, miles per hour
(d) Where the wind speed is known and an
adequate fetch for full development of the waves is
assumed, equation (5-8) may be used for waves of low
to moderate amplitude. This formula is not applicable to
very high waves (more than 25 to 30 feet).
5-3
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