HY8:Stilling Basins: Difference between revisions
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* [[WMS:HY-8 USBR Type IV Stilling Basin|USBR Type IV Stilling Basin]] | * [[WMS:HY-8 USBR Type IV Stilling Basin|USBR Type IV Stilling Basin]] | ||
* [[WMS:HY-8 Saint Anthony Falls (SAF Stilling Basin)|St. Anthony Falls (SAF) Stilling Basin]] | * [[WMS:HY-8 Saint Anthony Falls (SAF Stilling Basin)|St. Anthony Falls (SAF) Stilling Basin]] | ||
The maximum width of an efficient 'USBR' type stilling basin is limited by the width that a jet of water would flare naturally on the basin foreslope. The user is given the maximum flare value and is prompted to enter a basin width smaller than this value. If a 'SAF' basin is used, the basin width is set equal to the culvert width and the user is prompted to choose either a rectangular or flared basin depending on site conditions. Stilling Basins resemble the following illustration. | The maximum width of an efficient 'USBR' type stilling basin is limited by the width that a jet of water would flare naturally on the basin foreslope. The user is given the maximum flare value and is prompted to enter a basin width smaller than this value. If a 'SAF' basin is used, the basin width is set equal to the culvert width and the user is prompted to choose either a rectangular or flared basin depending on site conditions. Stilling Basins resemble the following illustration. | ||
[[Image:HY8image7.jpg]] | [[Image:HY8image7.jpg]] | ||
Variables from the figure | Variables from the figure | ||
* | * W<sub>0</sub> -- width of the channel | ||
* | * W<sub>B</sub> -- Width of the basin | ||
* | * y<sub>0</sub> -- Culvert outlet depth | ||
* | * Y<sub>1</sub> -- Depth entering the basin | ||
* | * Y<sub>2</sub> -- Conjugate depth | ||
* | * S<sub>0</sub> -- Slope of the channel | ||
* | * S<sub>T</sub> -- Slope of the transition | ||
* | * S<sub>S</sub> -- Slope leaving the basin | ||
* | * Z<sub>0</sub> -- ground elevation at the culvert outlet | ||
* | * Z<sub>1</sub> -- ground elevation at the basin entrance | ||
* | * Z<sub>2</sub> -- ground elevation at the basin exit | ||
* | * Z<sub>3</sub> -- Elevation of basin at basin exit (sill) | ||
* | * L<sub>T</sub> -- Length of transition from culvert outlet to basin | ||
* L -- Total basin length | * L -- Total basin length | ||
* | * L<sub>B</sub> -- Length of the bottom of the basin | ||
* | * L<sub>S</sub> -- Length of the basin from the bottom of the basin to the basin exit (sill) | ||
* | * T<sub>w</sub> -- Tailwater depth leaving the basin | ||
Warning for Stilling Basin Width | == Warning for Stilling Basin Width == | ||
Since the maximum basin width is a function of basin depth, the maximum width may decrease as the program increases the basin depth while converging on a solution. Therefore the maximum basin width may fall below the user's first choice for basin width. In this case, the user will be prompted for a new basin width. | Since the maximum basin width is a function of basin depth, the maximum width may decrease as the program increases the basin depth while converging on a solution. Therefore the maximum basin width may fall below the user's first choice for basin width. In this case, the user will be prompted for a new basin width. | ||
{{HY8Main}} | {{HY8Main}} | ||
Revision as of 21:21, 16 December 2011
The four types of Stilling Basins External Energy Dissipators available in the program:
The maximum width of an efficient 'USBR' type stilling basin is limited by the width that a jet of water would flare naturally on the basin foreslope. The user is given the maximum flare value and is prompted to enter a basin width smaller than this value. If a 'SAF' basin is used, the basin width is set equal to the culvert width and the user is prompted to choose either a rectangular or flared basin depending on site conditions. Stilling Basins resemble the following illustration.
Variables from the figure
- W0 -- width of the channel
- WB -- Width of the basin
- y0 -- Culvert outlet depth
- Y1 -- Depth entering the basin
- Y2 -- Conjugate depth
- S0 -- Slope of the channel
- ST -- Slope of the transition
- SS -- Slope leaving the basin
- Z0 -- ground elevation at the culvert outlet
- Z1 -- ground elevation at the basin entrance
- Z2 -- ground elevation at the basin exit
- Z3 -- Elevation of basin at basin exit (sill)
- LT -- Length of transition from culvert outlet to basin
- L -- Total basin length
- LB -- Length of the bottom of the basin
- LS -- Length of the basin from the bottom of the basin to the basin exit (sill)
- Tw -- Tailwater depth leaving the basin
Warning for Stilling Basin Width
Since the maximum basin width is a function of basin depth, the maximum width may decrease as the program increases the basin depth while converging on a solution. Therefore the maximum basin width may fall below the user's first choice for basin width. In this case, the user will be prompted for a new basin width.
