HY8:Tumbling Flow in Circular Culverts

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

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

v • e HY-8
Introduction:	Getting Started • Layout • Vena Contracta • Building a Project • Locate Project • Culvert Crossing Data • Run Analysis • Report Generation
Crossing and Culvert Data:	Crossings • Discharge Data • Roadway Data • Tailwater Data • Irregular Channel • Culvert Data • Site Data • Culvert Invert Data • Embankment Toe Data
Analysis	Project Units • Roadway Overtopping • Inlet Control Computations • Outlet Control Computations • Tables and Plots
Energy Dissipation	Scour Hole Geometry • Increased Resistance • Tumbling Flow • USBR Type IX Baffled Apron • Drop Structures • Stilling Basins • Streambed Level Structures
Methods	Aquatic Organism Passage • Low Flow Hydraulics
Troubleshooting	Differences from DOS HY-8 • Limitations • HY-8 User Manual

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