ERDC/CHL CHETN-IV-32
June 2001
PIPEDIAM(I) = D = Diameter of the cross-barrier pipe (in consistent units).
This defined format is similar to that of the standard IBTYPE= 4, 24 internal-barrier boundary
except that values for PIPEHT(I), PIPECOEF(I) and PIPEDIAM(I) must be specified.
Furthermore, as is the case with the standard internal-barrier boundary, the leaky internal-barrier
must be defined as an island with parallel front and back faces so that there is a one-to-one
correspondence between the nodes on the front face of the internal-barrier boundary and the
nodes on the back face. This correspondence is to allow the comparison of water levels on both
sides of the barrier, which is the basis of the cross-barrier flow computations. Only node
numbers on the front side of the barrier are provided as input for the array NBVV(K,I). Thus
global node numbers describing the front of the internal barrier are input sequentially and
defined as NBVV(K,I), where K = flow boundary segment and I = sequential flow boundary
node, for the front side of the internal-barrier boundary in a clockwise direction (this convention
has been standard for all internal boundaries) while the paired backside global node numbers are
specified in IBCONN(I).
All other information, BARINHT(I), BARINCFSP(I),
BARINCFSB(I), PIPEDIAM(I), PIPECOEF(I) and PIPEDIAM(I) are provided along with
NBVV(K,I) and IBCONN(I) for each front side node.
No changes are required in the unit 15 (control) input file to accommodate the leaky internal-
barrier boundary condition. All specified normal-flow external boundary and external/internal-
barrier normal-flow boundary information is output to the unit 16 output file with additional
detailed boundary segment information. Normal flows at either specified normal-flow external
boundary nodes or external/internal-barrier boundary nodes can be tracked using the specified
unit 61 and 62 station output file features with appropriately specified coordinates.
All input and output requirements and/or changes are thoroughly described in the html-based on-
line documentation file for ADCIRC Version 40.02 and higher.
The Web site is
http://www.unc.edu/depts/marine/C_CATS/adcirc/ and contains a full description of the model as
well as the input files described in the following examples.
Idealized Example 20c: Example 20c is a modified version of our standard test case for
verifying overtopping levees, which now includes the new feature, leaky barriers. The input files
for this case are the unit 14 and 15 files designated example20c.grd and example20c.inp,
respectively. These files can be obtained at http://www.unc.edu/depts/marine/C_CATS/adcirc/.
This case incorporates three internal-barrier boundaries that are shown in Figure 7. The first is
designated in the unit 14 input file as flow boundary no. 8 and encircles the southern low-lying
land region. This barrier has been set up to allow for both overtopping as well as leakage
through the barrier itself. The crown of this internal barrier occurs 0.6096 m (2.0 ft) above the
geoid. In addition to barrier overtopping, this barrier incorporates the leaky internal-barrier
boundary to account for the possibility of holes that can lead to cross-barrier flow. The leaky
internal-barrier boundary option is implemented with cross-barrier pipes that are located under
the crown of the barrier. This boundary must either be designated as IBTYPE = 5 or 25. In this
case we have designated IBTYPE = 25 so that the computed cross-barrier flow will be
implemented as a natural boundary condition. This specification generally avoids over-
constraining the system of equations and reduces the possibility of cross-barrier spurious modes.
In addition to the standard internal-barrier information, the user must designate the height of the
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