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<br />AUTOMATIC COMPUTATION OF STAGE-DISCHARGE RELATIONS AT CULVERTS 11
<br />
<br />beveling. wingwfllls, or projecting entrance.
<br />Adjustment for degree of contraction is part
<br />of the computer program.
<br />
<br />The HP and CP blocks on card 7 are for
<br />the headwater elevations and the discharge
<br />coefficients for pipes or pipe-arches. The
<br />CB12 block is for the constant-discharge
<br />coefficient for a rectangular box with types
<br />1 or 2 now. The discharge coefficient for
<br />type 3 flow in a rectangular box is a function
<br />of the. Froude number and is computed in the
<br />program using data from card 9. Use either
<br />the blocks for pipes and pip~-arches. or that
<br />for a rectangular box.
<br />
<br />List the four discharge coefficients and
<br />
<br />four l}fadwater e~J~ns corresponding to
<br />
<br />elevatIons at .
<br />../-----;::~'- ~
<br />- -, ,---.-.- ,
<br />~d _., --- I
<br />O-times-D. plus the( z elevation;
<br />0.7 D + z elevation."--_!'..__.. /
<br />1.1 D + Z elevation, and
<br />1. 5 D + Z elevation.
<br />
<br />The headwater elevations must be listed in
<br />ascending order. Be sure that HP4 is equal
<br />to or greater than 1. 5 D + z elevation (not
<br />rounded off): if it is not, the computation
<br />halts,
<br />
<br />The headwater elevations are listed in
<br />columns 1- 6, 14-19, 27-32, and 40- 45; and
<br />the coefficients in columns 8-11, 21-24, 34-
<br />37, and 47-50. Fixed decimals are in col-
<br />umns 4, 9, 17, 22, 30, 35, 43, and 48.
<br />
<br />CB12 is in columns 62-65 with a fixed dec-
<br />imal in column 63.
<br />
<br />Complete the card by adding the sequence
<br />number (previous sequence number~ plus O.
<br />
<br />The card number, column 80. is 7.
<br />
<br />Card 8 - Discharge Coefficients
<br />Types 4, 5, 6
<br />
<br />The H5 and C5 blocks are for the head-
<br />water elevations and the discharge -coefficients
<br />for type 5 now at four specific headwater ele-
<br />vations. H5 values are independent of the
<br />W value on card 2, List the net, or ad-
<br />m~
<br />justed. coefficients and the headwater ele-
<br />vations corresponding to el~vations at 1. 5; ,
<br />, ._ 2.0, 3.0, and 5.0 times D, plus the z ele~
<br />~_~or all types of cu~vert barrels. The
<br />
<br />---.-- - ------ --
<br />
<br />headwater elevations must be listed in as-
<br />cending order. Be sure H5-1 h; equal to or
<br />less than 1. 5 D + z elevation (not rounded
<br />off), and that H5-4 is equal to or greater than
<br />5.0 D + z elevation; otherwise~ the solution
<br />for type 5 flow between the extremes,
<br />(1. 5 D + z) and (5.0 D + z), cannot be accom-
<br />plished.
<br />
<br />At and below the elevation of 1. 5 D + Z ele-
<br />vation, the discharge coefficient takes the
<br />value it is assigned at elevation 1.5 D + z ele-
<br />vation; at and above the elevation of 5. 0 D
<br />+ Z elevation. the coefficient takes the value
<br />assigned at elevation 5.0 D + Z elevation.
<br />Between the elevations of 1. 5 D + z elevation
<br />and 5. 0 D + z elevation, the correct discharge
<br />coefficient is computed in the program.
<br />
<br />The headwater elevations are listed in
<br />columns 1-6, 14-19, 27-32, and 40-45; and
<br />the coefficients are listed in columns 8-11.
<br />21-24. 34-37, and 47-50. Fixed decimals
<br />are In columns 4, 9, 17, 22, 30, 35, 43. and
<br />48~
<br />
<br />The block C46 is the constant- discharge
<br />coefficient for all. conditions of type 4 and
<br />type 6 now, The coefficient is listed In col-
<br />umns 62-65 with a fixed decimal In column
<br />63.
<br />
<br />Complete the card by adding the sequence
<br />number (previous sequence number, plus 1).
<br />
<br />The card number. column 80, is 8.
<br />
<br />Card 9 - Culvert Barrel Data
<br />
<br />Eight items related io the description of
<br />the culvert barrel are entered on card 9.
<br />Also, adjustment factors kr' kw' and ka for
<br />
<br />the discharge coefficient are listed, but only
<br />if type 3 flow in a box culvert is to be com-
<br />puted. There is an option to include the in-
<br />fluence from tailwater.
<br />
<br />Column 1. --Tc is the type of culvert barrel.
<br />Use the integer 1 for a circular pipe, 2 for a
<br />box, or g fOI"a pipe- arch.
<br />
<br />Columns 4-9, --BASE ELEV. is the survey
<br />datum elevation of the culvert invert at the
<br />outlet. Heads are measured above this point
<br />as a base. The fixed decimal is in column 7.
<br />
<br />Columns 11-16.--z ELEV. is the survey
<br />
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