HY8:Tumbling Flow in Box Culverts: Difference between revisions

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Height, which must be equal to or greater than the height of the culvert.
Height, which must be equal to or greater than the height of the culvert.




The following figures show two configurations of tumbling flow dissipators.
The following figures show two configurations of tumbling flow dissipators.


 
[[Image:HY8image11.jpg]]
[[Image:HY8image11.jpg]]


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* L -- Length from beginning of one roughness element  to the beginning of the next roughness element.
* L -- Length from beginning of one roughness element  to the beginning of the next roughness element.
* h -- Height of roughness element
* h -- Height of roughness element
* h1 -- Distance from top of dissipator to ceiling of culvert
* h<sub>1</sub> -- Distance from top of dissipator to ceiling of culvert
* h2 -- Height of splash shield on ceiling of culvert
* h<sub>2</sub> -- Height of splash shield on ceiling of culvert
* h3 -- Culvert rise
* h<sub>3</sub> -- Culvert rise
* yn -- Tailwater depth
* y<sub>n</sub> -- Tailwater depth
* Di -- Diameter of roughened section (opening)




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Variables from the figure
Variables from the figure


* L1 -- Length from beginning of one roughness element to the beginning of the next roughness element.
* L<sub>1</sub> -- Length from beginning of one roughness element to the beginning of the next roughness element.
* LT -- Transition Length
* L<sub>T</sub> -- Transition Length
* hi -- Height of roughness element
* h<sub>i</sub> -- Height of roughness element
* yc -- Critical depth
* y<sub>c</sub> -- Critical depth
* θ -- slope of the culvert bottom expressed in degrees
* θ -- slope of the culvert bottom expressed in degrees
* φ -- jet angle, taken as 45 degrees
* φ -- jet angle, taken as 45 degrees

Revision as of 20:30, 16 December 2011

The input variables required for this calculation is the following:

Roughness Spacing to Height Ratio -- The user must select a value of either 8.5 or 10 for the ratio of roughness element spacing divided by roughness element height. If after calculations the flow through the roughened section of the culvert impacts on the culvert roof, then the minimum enlarged section height needed to correct this problem will be given and the user will be prompted to enter a value equal to or larger than this minimum value.

Height, which must be equal to or greater than the height of the culvert.


The following figures show two configurations of tumbling flow dissipators.


HY8image11.jpg

Variables from the figure

  • L -- Length from beginning of one roughness element to the beginning of the next roughness element.
  • h -- Height of roughness element
  • h1 -- Distance from top of dissipator to ceiling of culvert
  • h2 -- Height of splash shield on ceiling of culvert
  • h3 -- Culvert rise
  • yn -- Tailwater depth


HY8image12.jpg

Variables from the figure

  • L1 -- Length from beginning of one roughness element to the beginning of the next roughness element.
  • LT -- Transition Length
  • hi -- Height of roughness element
  • yc -- Critical depth
  • θ -- slope of the culvert bottom expressed in degrees
  • φ -- jet angle, taken as 45 degrees