online_inherently_stable:    Computation of the inherently stable channel   [Beta version 1.0 - 160529]



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 ]

Thank you for running online_inherently_stable   [160530 19:30]