Once the grid spacing and extent have been chosen, different algorithms
(linear, inverse distance, kriging, etc.) can be used to interpolate the seabed
elevation data (x,y,z) onto a uniform rectangular grid. Land regions and
impermeable harbor structures are then mapped onto the grid as positive
elevations. The grid data should then be saved as an ASCII file in the grid file
format described in Appendix D.
Preparation of Damping Grid File
The external boundaries of the computational grid are considered to be fully
reflecting wall boundaries unless it is specified as a wave generation boundary.
Damping regions have to be placed inside the domain to absorb outgoing waves.
The damping regions should be of the order of half a wavelength wide with a
quadratic variation of the nondimensional damping coefficient, nd(x,y), from 0
to 1 at the wall boundary.
A utility program GEN_DAMP (Appendix E) has been provided to generate
the damping file given the location of the damping layers (North, South, East, or
West grid boundaries), the width of the damping layer, and the nondimensional
damping strength at the end wall. The damping file is stored as an ASCII file in
the grid file format described in Appendix D.
Preparation of Porosity Grid File
Porosity layers are used to simulate partial reflection and transmission
through porous structures such as breakwaters. The porosity grid file contains
information on the porosity distribution n(x,y) over the computational grid with a
value of 1.0 for water points. A porosity value of 0.4 is typically used for break-
waters. Regions with small porosity values (n < 0.1) such as breakwater core
layers should be treated as impermeable regions and mapped as land points in the
bathymetry file.
A utility program MAP_POROSITY (Appendix E) has been provided to
create a porosity file given the breakwater boundaries as a set of discrete (x,y)
points. The porosity file should be saved as an ASCII file in the grid file format
described in Appendix D.
Creation of Simulation Parameter File
All the input parameters required to run BOUSS-2D is stored in an ASCII
text file, referred to as a simulation parameter file (.par). The file is a free format
file with names of the simulation parameters and associated values not con-
strained to any particular rows or columns. The full colon (:) character is used at
the beginning of lines containing parameter names and values, and the pound (#)
character is used to delineate sections of a line with comments. Due to the
multitude of options available for the input file, it is recommended that the inter-
active program Pre_BOUSS2D be used to create it. Pre_BOUSS2D can be run
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Chapter 4 Setting Up and Running BOUSS-2D
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