warrantée! by the size or importance of the problem. These methods are
recommended only if a computer is available. A hrief description of
these methods and references to them follows.
Solutions to the basic équations given can be obtained by the techniques of numerical intégration. The differential équations are appfoximated by finite différences resulting in a set of équations referred to
as the numerical analogs. The finite-difference analogs, together with
known input data and properly specified boundary conditions, allow évaluation at discrète points in space of both the fields of transport and water
level élévations. Because the équations involve a transient problem,
steps in time are necessary; the time interval required for these steps is
restricted to a value between a few seconds and a few minutes depending on
the resolution desired and the maximum total water depth. Thus solutions
are obtained by a répétitive process where transport values and water-level
élévations are evaluated at ail prescribed spatial positions for each time
level throughout the temporal range.
These techniques hâve been applied to the study of long-wave propagation in various water bodies by numerous investigators. Some investigations of this type are listed below. Mungall and Matthews (1970) developed a variable-boundary, numerical tidal model for a fjord inlet. The
problem of surge on the open coast has been treated by Miyazaki (1963),
Leendertse (1967), and Jelesnianski (1966, 1967, and 1970). Platzman
(1958) developed a model for computing the surge on Lake Michigan resulting from a moving pressure front, and also developed a dynamical wind tide
model for Lake Erie. (Platzman, 1963.) Reid and Bodine (1968) developed
a numerical model for computing surges in a bay System taking into account
flooding of adjacent low lying terrain and overtopping of low barrier
islands.
b* Simplified Techniques for Determining Storm Surge. The techniques described here for the détermination of storm surge are simple, and
it is possible to carry out ail storm surge calculations manually, using a
desk calculator or slide rule. In most cases, however, it is désirable to
employ a digital computer for the computations to reduce the effort and to
improve accuracy. It is sometimes possible to estimate surge with satisfactory accuracy using a set of simplified équations, if the particular
problem is not too complex, and if the simplified technique can be verified
rom actual prototype field data. Simpler schemes for computing storm
drL° tamed by including only those phenomena that appear signifiC
♦ u ç 6 1^vestlSat^on5 thus some of the less important terms are
omitted from Equations 3-50, 3-51 and 3-52.
W Storm Surge on the Open Coast
t h Q O k ~ 1 1 ._ _ "" X" . ■
U J Storm Surge on the Open Coast. Océan basins are large a
deep beyond the shallow waters of the Continental Shelf. The expanse o
océan basins permits large tropical or extratropical storms to be situa
entirely over water areas allowing tremendous energy to be transferre
from the atmosphère to the water. Wind-induced surface currents, when
moving from the deep océan to the coast, are impeded by the shoaling
bottom, causing an increase in water level over the Continental Shelf*
3-96
recommended only if a computer is available. A hrief description of
these methods and references to them follows.
Solutions to the basic équations given can be obtained by the techniques of numerical intégration. The differential équations are appfoximated by finite différences resulting in a set of équations referred to
as the numerical analogs. The finite-difference analogs, together with
known input data and properly specified boundary conditions, allow évaluation at discrète points in space of both the fields of transport and water
level élévations. Because the équations involve a transient problem,
steps in time are necessary; the time interval required for these steps is
restricted to a value between a few seconds and a few minutes depending on
the resolution desired and the maximum total water depth. Thus solutions
are obtained by a répétitive process where transport values and water-level
élévations are evaluated at ail prescribed spatial positions for each time
level throughout the temporal range.
These techniques hâve been applied to the study of long-wave propagation in various water bodies by numerous investigators. Some investigations of this type are listed below. Mungall and Matthews (1970) developed a variable-boundary, numerical tidal model for a fjord inlet. The
problem of surge on the open coast has been treated by Miyazaki (1963),
Leendertse (1967), and Jelesnianski (1966, 1967, and 1970). Platzman
(1958) developed a model for computing the surge on Lake Michigan resulting from a moving pressure front, and also developed a dynamical wind tide
model for Lake Erie. (Platzman, 1963.) Reid and Bodine (1968) developed
a numerical model for computing surges in a bay System taking into account
flooding of adjacent low lying terrain and overtopping of low barrier
islands.
b* Simplified Techniques for Determining Storm Surge. The techniques described here for the détermination of storm surge are simple, and
it is possible to carry out ail storm surge calculations manually, using a
desk calculator or slide rule. In most cases, however, it is désirable to
employ a digital computer for the computations to reduce the effort and to
improve accuracy. It is sometimes possible to estimate surge with satisfactory accuracy using a set of simplified équations, if the particular
problem is not too complex, and if the simplified technique can be verified
rom actual prototype field data. Simpler schemes for computing storm
drL° tamed by including only those phenomena that appear signifiC
♦ u ç 6 1^vestlSat^on5 thus some of the less important terms are
omitted from Equations 3-50, 3-51 and 3-52.
W Storm Surge on the Open Coast
t h Q O k ~ 1 1 ._ _ "" X" . ■
U J Storm Surge on the Open Coast. Océan basins are large a
deep beyond the shallow waters of the Continental Shelf. The expanse o
océan basins permits large tropical or extratropical storms to be situa
entirely over water areas allowing tremendous energy to be transferre
from the atmosphère to the water. Wind-induced surface currents, when
moving from the deep océan to the coast, are impeded by the shoaling
bottom, causing an increase in water level over the Continental Shelf*
3-96