online_wsprofiles_21: M1 water-surface profile
- The php script [program] online_wsprofiles_21
calculates an M1 water-surface profile in a prismatic open channel using the direct-step method (Chow, V. T.: Open-channel hydraulics, McGraw-Hill, 1959).
- The program calculates normal depth
based on the geometric and hydraulic input data. Newton's iteration is used to solve the nonlinear equations.
- An M1 profile is subnormal, subcritical, and mild (see figure).
The calculated gradually varied flow depth varies between the specified flow depth
at the downstream boundary and [it is asymptotic to] normal depth upstream.
- There are five required input variables: discharge Q, bottom width B, side slope z, bottom slope So, and Manning's n.
- For the downstream boundary condition, you can specify a suitable input flow depth.
Alternatively, if the input flow depth box is left blank,
the program will use a value close to normal depth (1.01 * yn) instead.
- The program echoes the input data. Internally calculated normal depth is echoed with five-decimal (5) accuracy.
- For the input flow depth, you can enter
any suitable [subcritical] subnormal flow depth, i.e., a flow depth greater than normal depth.
Leave this box blank if you want the program to use a value close to
normal depth (1.01 * yn) [In general, this option is not recommended, because the M1 profile would be very close to uniform flow].
- You can enter the desired number of computational intervals n. The suggested range is 50-200. A higher number
means higher computational accuracy.
Leave this box blank if you want the program to set the default value at 100.
- You can enter the desired number of tabular output intervals m. The suggested range is 10-100. A higher number
means more detailed [longer] output.
Leave this box blank if you want the program to set the default value at 10.
- A table with thirteen (13) columns: output interval index k, [flow] depth (m),
[flow] area (m2), velocity (m/s), velocity head (m), specific head (m), wetted perimeter (m), hydraulic radius (m),
friction slope (m/m), average [friction] slope (m/m), specific head difference (m), length increment (m), and total [channel] length (m).
- The number of computational intervals n and the number of tabular output intervals m are printed for reference.
- The calculated normal depth and normal-depth Froude number are printed for reference. If the normal-depth Froude number
exceeds 0.99, execution is halted (see error message No. 7 below).
- The current version is written in SI [metric] units.
- Enter only positive [nonzero] numbers for discharge, Manning's n, and bottom slope.
Failure to do this will trigger an error message and halt execution (Error messages No. 1: A, B, and C, respectively).
- Enter only nonnegative [zero or greater] numbers for bottom width and side slope.
Failure to do this will trigger an error message and halt execution (Error messages No. 2: A and B, respectively).
- Bottom width and side slope cannot be zero at the same time.
Failure to do this will trigger an error message and halt execution (Error message No. 3).
- A Manning's n value outside of the range 0.008-0.250
will trigger an error message and halt execution (Error message No. 4).
- A bottom slope outside of the range 0.000005-0.05
will trigger an error message and halt execution (Error message No. 5).
- An input flow depth less than or equal to the calculated normal depth
will trigger an error message and halt execution (Error message No. 6).
- A normal-depth Froude number greater than 0.99
will trigger an error message and halt execution (Error message No. 7).
Thank you for running online_wsprofiles_21. Please call again. [Version 1.0.0, 070430]