Full Equations Utilities (FEQUTL) Model for the Approximation
of Hydraulic Characteristics of Open Channels and Control
Structures During Unsteady Flow
Purpose: An input file for HEC-2 (U.S. Army Corps of Engineers, 1990a) is scanned in the HEC2X command, the cross sections in the file are read, and either the cross-section table or the input for the CHANNEL command (section 5.2) or the FEQX command (section 5.8) is computed.
Notes: The input files for HEC-2 need not be changed. Lines that are not needed are skipped in HEC2X computations. The only lines detected and used are X1, X4, GR, NC, NH, and ER Lines in the HEC-2 input. Limited checking of the data is done in HEC2X, but it is assumed that detailed checking has already been done on the input data.
LINE 1|
CHAR4 must be MODE. MODE specifies the mode of analysis applied in HEC2X. A cross-section table is computed directly from the HEC-2 input in the DIRECT mode. Input for the FEQX command (section 5.8) is computed from the HEC-2 input in the INDIRECT mode. In the INDIRECT mode, it is possible to modify the FEQX input to correct for any problems in the subdivision of the cross section in the HEC-2 input. In the last mode, a variant of INDIRECT called CHANNEL, the input for a CHANNEL command (section 5.2), is computed and placed in a file. The flow lengths between sections are used with the CHANNEL command to compute estimates of the sinuosity for the cross sections. The keywords CHANNEL, DIRECT, and INDIRECT also can be in lowercase. |
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CHAR6 must be INFILE. INFILE is the file name of the file containing the HEC-2 input. |
LINE 3
Variables: CHAR7, OUTFIL
Format: A7, 1X, A64
Example: OUTFILE = HECFEQX
Explanation:
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CHAR7 must be OUTFILE. OUTFILE is the file name to use in storing the FEQUTL input when MODE = INDIRECT or MODE = CHANNEL. OUTFILE must still appear when MODE = DIRECT, but the file name may be left blank. |
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CHAR8 must be OPTIONS: . CIN are the options to use in computing the table for the FEQX input. These options are the same as for the FEQX command (section 5.8). |
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CHAR8 must be BEGTAB #=. BEGTAB is the table number for the first cross section found in the HEC-2 input. TABINC is the table number increment (TABINC) added to BEGTAB (and all subsequent table numbers) resulting in the table numbers for all cross sections found in the HEC-2 input. The table increment may be negative as shown. |
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CHAR8 must be "BEGSTAT = ". BEGSTA is the beginning station for the first cross section. STADIR indicated that the distance between cross sections in the HEC-2 input should be added (+1) or subtracted (-1) from BEGSTAT and all subsequent stations along the channel. Thus, the stations may increase or decrease as the file named in INFILE (Line 2) is processed. If STADIR is omitted, it is assumed that the increments are positive. The main-channel length increments are used in HEC2X to compute the stations. |
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CHAR4 must be SFAC. SFAC is the conversion factor from the units used in HEC2 for the distance between cross sections to the units in the stationing in the unsteady-flow model. SFAC is a divisor on the distances used in HEC2. If the distances in HEC2 are in feet, as in most cases, then SFAC = 5,280 will produce stations along the channel in miles. |