HY8:Increased Resistance in Circular Culverts

The input variables required for this calculation is the following:

L/D_i — Ratio of roughness element spacing divided by the diameter of the culvert opening at the roughness element. (Range = .05 to 1.5)
h/D_i — Ratio of roughness element height divided by the diameter of the culvert opening at the roughness element. (Range = .005 to .1).
L_r/P_i — Ratio of the roughness length to inside perimeter (Range = 0.0 to 1.0)
Diameter of roughened section (Opening, D_i)

The following figure shows the flow regimes and variables for an increased resistance energy dissipator implemented in a circular culvert.

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
D_i — diameter of roughened section (opening)

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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