HOW TO USE THIS SCRIPT
This online script calculates hydraulic parameters for the
inherently stable and associated conditionally stable channels.
The inherently stable channel is that for which the neutrally stable
Froude number is infinity (Fns ⇒ ∞). Since this number is an asymptotic value,
a value of 10,000
is assumed to be as close to infinity as practical.
The conditionally stable channels
constitute a family of channel cross sections for which a neutrally stable
Froude number, less than infinity (∞), may be specified. The suitable range
of neutrally stable Froude numbers for the conditionally stable channel varies
from 3 to less than 10,000. These channels are stable
throughout a wide range of Froude numbers, thus eliminating the risk of
roll waves or pulsating waves.
To use the script, enter applicable hydraulic data on the left input column
and choose a neutrally stable Froude number on the right input column (a choice of 10 values, labeled from A to J).
The depth interval Δh is internally set to 0.0001 m.
The actual number of computational depth intervals
in the upper subsection varies with the
relative depth hu'.
The length of tabular output is specified as input.
The default number of output lines is 10.
The tabular output shows typical hydraulic variables,
wherein the half top width (6th column) depicts the shape
of the selected channel type, either: (1) the
inherently stable channel, or (2) any of the indicated conditional stable channels.
A choice of ten (10) neutrally stable Froude numbers is provided,
covering the range 3 ≤ Fns ≤ 10,000.
Additional details may be found in the accompanying article.
♦ WARNING ⇒ The following input values will trigger a fatal error message:
- Half bottom width: B* ≤ 0
- Depth of lower subsection: ho ≤ 0
- Side slope of lower subsection: z < 0
- Relative depth: hu' ≤ 0
- Channel slope: So < 0.01
- Manning's: n < 0.008
- No. of output lines : 0 ≤ NL
≤ 10,000 [ Leave blank to set default value of 10 ]