CETN-II-10
REVISED-
N-LINE (BATHYMETRIC CHANGES) MODEL
PURPOSE:
The purpose of this technical note is to present an
update of the status of the N-line model which was first reported
in 1983.
The original model was provided CERC (Perlin and Dean,
1983) for the purpose of simulating sediment transport and
bathymetric changes in the vicinity of coastal structures.
Following that initial release, several improvements and
enhancements were made to the code in order to make the model
easier to use and more general in scope.
The latest version of
the model and a detailed users guide are now available (Scheffner
and Rosati, 1987).
GENERAL:
The N-line model utilizes empirical sediment transport
relationships to compute both along-shore and on- and off-shore
sediment transport in the vicinity of coastal structures as a
function of a specified off-shore wave climate.
Effects of both
refraction and diffraction are included.
The model utilizes
these computed distributions in a sediment continuity equation to
predict shoreline and bathymetric changes in the vicinity of
various coastal structures. Presently, the model can simulate
single or multiple shore perpendicular groins or jetties,
multiple detached breakwaters, dredged material disposal, and
beach nourishment.
The primary limitation of the model is due to
the basic equilibrium profile assumption that the offshore depth
increases continually in the offshore direction.
This limitation
precludes the modeling of offshore bars or troughs.
A discussion
of the capabilities and limitations o f the model are presented in
the users manual. The model is presently available for use on a
Cyber 176 at Cybernet, the Corps' contract computer service.
INPUT REQUIRED: The present version of the model includes an
interactive program for constructing an input data file.
Input
data include the offshore wave height, period, and direction in
addition to a grain size descriptive of the location and the
geometry of the modeled area. Input for the numerical model
include a time step, along-shore grid spacing, and contour line
specification.
A complete description of the input variables is
provided in the users manual which includes specific examples of
input files and output results.
The N-line model requires the
International Mathematical and Statistical Library, Inc. (IMSL)
subroutine package LEQTIB.
If the user's computer center does
not have access to this package, the user must supply a
subroutine to facilitate the solution of a banded storage mode
matrix.
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