ERDC/CHL CHETN-I-69
March 2005
size of the damping layer. The damping region extends the width on either side of the cell string. The
damping value is a nondimensional damping coefficient that is allowed to vary from 0.0 to 1.0. No
damping will occur when a value of 0.0 is used. Waves will be damped when a value of 1.0 is used
along the side boundaries. A typical value for shoreline is 0.1. The default damping value is 1.0.
SMS will assign the value specified at the cell string and ramp down to 0.0 at a distance of "width"
from the cell string.
(3) Porosity BC. Porosity boundary conditions are used to simulate partial wave reflection and
transmission through surface-piercing porous structures such as breakwaters. Enter a physical width
into the "Width" edit field to specify the size of the porous structure. Like with the damping regions,
this width is extended on both sides of the cell string. The porosity value is a nondimensional
porosity coefficient that is allowed to vary from 0.0 to 1.0. A value of 0.0 corresponds to an
impervious structure, while a value of near 1.0 would correspond to a highly porous structure.
Typical porosity for stone type breakwaters is 0.4. The default porosity value is 1.0.
(4) Wavemaker BC. The wavemaker option is only available when a single cell string is selected
and that cell string lies in a single column or row (straight line). Legal cell strings can be created
using the SHIFT key when creating cell strings, using automatically created cell strings along a grid
boundary, or by creating short cell strings. The extent and position of the wavemaker can be
modified using I,J indices in the dialog. BOUSS-2D generates waves emanating from this cell string.
The properties of the waves are defined using the Wave Generator Properties dialog (described
later) that is accessed through the Options button. The edit fields are used to position and size the
wavemaker in the computational domain. The first two values are the Start and End cells of the
wavemaker along the column or row that is specified by the third value, which is the Offset value.
The Start and End values are limited to the number of cells in either the I- or J-direction, and the
Offset value is limited to the number of rows or columns.
When the OK button is clicked, a check is done to see if the wavemaker cell string is at a constant
depth. If the depth varies by more than 20 percent and the wavemaker is on the edge of the grid (not
internal), the user is asked whether to force constant depth along the wavemaker cell string or not. If
so, the grid is extended to allow the wavemaker to be at the deepest elevation along the string, with a
maximum slope of 1:10 from the existing grid to the new wavemaker position. A Wave Calculator is
provided as part of BOUSS-2D interface in SMS (see Appendix B) to assist users in the preparation
of wave input parameters required by the model. Note that the BOUSS-2D | Assign BC menu item is
disabled any time multiple wavemakers are selected or if a wavemaker and one or more other cell
strings are selected.
Runup/overtopping: To assist the user in the design of coastal structures, the interface
f.
includes a one-dimensional (1-D) wave runup and overtopping calculator. This utility runs a 1-D
simulation with BOUSS-1D based on user-specified parameters. To access the 1D Runup and
Calculators dialog. The BOUSS-2D Calculators dialog is always in the BOUSS-2D interface.
Input to the 1D Runup and Overtopping calculator is organized into a spreadsheet. The first row of
the input parameters spreadsheet is fixed and will contain the column titles given in Table 4. The
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