HY8:Tumbling Flow in Circular Culverts

The only input variable required for this calculation is the following:

• Diameter of enlarged culvert

The following figures show implementations of tumbling flow within circular culverts along with the variables used to design the energy dissipator.

Variables from the figure

• D -- Diameter of original culvert
• V_n -- Tailwater velocity
• y_n -- Tailwater depth
• L -- Length from beginning of one roughness element to the beginning of the next roughness element.
• h -- Height of roughness element
• h₁ -- length from top of roughness element to enlarged culvert ceiling
• h₂ -- height of splash shield on enlarged culvert ceiling.
• h₃ -- rise of enlarged culvert.

Variables from the figure

• D -- Diameter of original culvert
• D₁ -- Diameter of enlarged culvert
• D_i -- Diameter of roughened section
• h -- Height of roughness element
• L -- Length from beginning of one roughness element to the beginning of the next roughness element.

Variables from the figure

• D -- Diameter of original culvert
• T -- Water surface width at critical flow condition
• y -- Depth of flow