Model help:BackwaterWrightParker: Difference between revisions
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| m | | m | ||
|- | |- | ||
| D | | D<sub>50</sub> | ||
| median grain size (sand) | |||
| mm | |||
|- | |||
| D<sub>90</sub> | |||
| grain diameter such that 90% of the distribution is finer | | grain diameter such that 90% of the distribution is finer | ||
| mm | | mm | ||
| Line 133: | Line 137: | ||
| bed slope | | bed slope | ||
| - | | - | ||
|- | |- | ||
| Q | | Q | ||
| flow discharge | | flow discharge | ||
| m<sup>3</sup> / s | | m<sup>3</sup> / s | ||
|- | |- | ||
| L | | L | ||
| Line 157: | Line 153: | ||
| minimum shear stress due to skin friction | | minimum shear stress due to skin friction | ||
|- | |- | ||
|- | |-- | ||
| Fr<sub>d</sub> | | Fr<sub>d</sub> | ||
| Froude number | | downstream Froude number | ||
| m | | m | ||
|- | |- | ||
| Line 174: | Line 166: | ||
| x | | x | ||
| downstream coordinate | | downstream coordinate | ||
| m | |||
|- | |||
| ξ<sub>d</sub> | |||
| downstream water surface elevation, must be larger than the beginning point water surface elevation | |||
| m | | m | ||
|- | |- | ||
| η | | η | ||
| bed surface elevation | | bed surface elevation | ||
| m | | m | ||
|- | |- | ||
| Line 200: | Line 192: | ||
If the minimum shear stress due to skin friction τ<sub>s,min</sub>, calculation bombs at any point the program will end. | If the minimum shear stress due to skin friction τ<sub>s,min</sub>, calculation bombs at any point the program will end. | ||
If the height due to skin friction | If the height due to skin friction H<sub>s</sub>, calculation bombs, the program will assign the last value in the calculations to H<sub>s</sub>. | ||
If the H<sub>norm</sub> calculation bombs, the value for H<sub>norm</sub> is not outputted, but this does not affect the other values that are calculated. | If the H<sub>norm</sub> calculation bombs, the value for H<sub>norm</sub> is not outputted, but this does not affect the other values that are calculated. | ||
This program requires a given downstream water water elevation, | This program requires a given downstream water water elevation, ξ<sub>d</sub>, such that Fr<sub>d</sub> < 1, because the flow is assumed subcritical, and the program will alert the user and quit if the condition is not met. | ||
==Examples== | ==Examples== | ||
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==Links== | ==Links== | ||
* [[http://csdms.colorado.edu/wiki/Model:BackwaterWrightParker Model:BackwaterWrightParker]] | |||
[[Category:Utility components]] | |||
Revision as of 16:15, 11 May 2011
BackwaterWrightParker
This is used to calculate backwater curves in sand-bed streams, including the effects of both skin friction and form drag due to skin friction.
Model introduction
This program calculates backwater curves over a sand-bed stream with a specified spatially constant bed slope S. The calculation uses the hydraulic resistance formulation of Wright and Parker (2004) (without the flow stratification correction), as well as calculating the normal depth.
Model parameters
Uses ports
This will be something that the CSDMS facility will add
Provides ports
This will be something that the CSDMS facility will add
Main equations
A list of the key equations. HTML format is supported; latex format will be supported in the future
| Symbol | Description | Unit |
|---|---|---|
| R | sediment specific gravity, R+1 | - |
| B | channel width | m |
| D50 | median grain size (sand) | mm |
| D90 | grain diameter such that 90% of the distribution is finer | mm |
| S | bed slope | - |
| Q | flow discharge | m3 / s |
| L | reach length | m |
| M | number of spatial intervals | |
| τs,min | minimum shear stress due to skin friction | |
| Frd | downstream Froude number | m |
Output
| Symbol | Description | Unit |
|---|---|---|
| x | downstream coordinate | m |
| ξd | downstream water surface elevation, must be larger than the beginning point water surface elevation | m |
| η | bed surface elevation | m |
| H | flow depth | m |
| Hs | flow depth due to skin friction | m |
Notes
- Note on input parameters:
If the minimum shear stress due to skin friction τs,min, calculation bombs at any point the program will end.
If the height due to skin friction Hs, calculation bombs, the program will assign the last value in the calculations to Hs.
If the Hnorm calculation bombs, the value for Hnorm is not outputted, but this does not affect the other values that are calculated.
This program requires a given downstream water water elevation, ξd, such that Frd < 1, because the flow is assumed subcritical, and the program will alert the user and quit if the condition is not met.
Examples
An example run with input parameters, BLD files, as well as a figure / movie of the output
Follow the next steps to include images / movies of simulations:
- Upload file: http://csdms.colorado.edu/wiki/Special:Upload
- Create link to the file on your page: [[Image:<file name>]].
See also: Help:Images or Help:Movies
Developer(s)
References
- Wright, S. and G. Parker, 2004, Flow resistance and suspended load in sand-bed rivers: simplified stratification model, Journal of Hydraulic Engineering, 130(8), 796-805.
