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SED2D-WES Version 4.3 Beta
3.5
Description of Card Image Input Data
Input to the program consists of card image data in data files. The following paragraphs describe the
input data in detail.
Information cards (T1,T2,T3,$D). These cards contain descriptive information used to identify a model run. As
many T1 and T2 cards can be used as are needed. The final title card must be a T3 card. Information on the T3
card is saved with the program output files (along with data management banners, if used), so it can be used to
identify the data file. The $D card permits the user to tag the beginning date of simulation for information
purposes (but this information is not used by the program).
Run control cards ($L1,$L2, $H, END, STOP, TO, TR, EF). These cards are used to control various aspects of
program control. The $L1 and $L2 cards are used to specify which input and output files the program will use.
The END card signals the end of the card list pertaining to a specific time step. One END card must be supplied
for every time step. The STOP card signals the end of the card list pertaining to the entire simulation period.
The $H card is used to control HOTSTART runs of the program. In a coldstart, a model run begins fresh,
not using the results of any previous run as a starting point. In a hotstart, some of the variables, such as
concentration or bed thickness, begin with values that were computed in a previous run. The files needed for
hotstarting a model run are written if so requested on the $L2 card . In order to make a hotstart run, first submit a
coldstart model run in which bed structure and/or concentrations and bed elevation changes are saved (see $L2
card). Then submit a run with the appropriate hotstart switches on the $H card, and specify the appropriate
hotstart unit numbers on the $L1 card.
In a coldstart run, all of the important processes must spin - up from an artificial condition such as a
uniform sediment concentration field. The spin - up time is the length of time a simulation must run before the
solution has recovered from the artificial initial condition. For example, in a sand bed problem, if the initial
sediment concentrations are too low in one area the bed may erode during spin - up until an equilibrium
concentration is reached. This may happen even if the prototype bed is stable in that area. To overcome this
problem, a hotstart run would be made in which concentrations are hotstarted from the previous run, but bed
structure and bed elevation changes are coldstarted.
The TO card specifies the frequency for printing the binary solution. The TR card specifies the frequency
for printing to the ASCII output file, and provides the user with options for the volume of information to be
printed. The primary purpose of the trace printout controls is to assist in diagnosing problems with a run, but they
also provide for printing of some parameters that may be useful in interpreting model results. If a trace printout is
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WORKING DRAFT
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