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The three most common methods of computing friction effects fluid flow are the Chezy equation, the Darcy-Weisbach equation, and the Manning equation. For open channel flow, the Manning equation is the most common method used.  
The three most common methods of computing friction effects fluid flow are the Chezy equation, the Darcy-Weisbach equation, and the Manning equation. For open channel flow, the Manning equation is the most common method used.  


“The selection of Manning’s n values is important in the computation of water surface profiles and flow in open channels. The selected values should be representative of flow conditions at the cross section location. The cross section can be subdivided into several segments to properly represent the resistance to flow within a cross section. Normally, a natural cross section is subdivided into three segments: channel, right and left overbanks. The overbank segments can be further subdivided depending on the conditions. Manning’s n values can vary with depth of water within a segment…
“The selection of Manning’s n values is important in the computation of water surface profiles and flow in open channels. The selected values should be representative of flow conditions at the cross section location. The cross section can be subdivided into several segments to properly represent the resistance to flow within a cross section. Normally, a natural cross section is subdivided into three segments: channel, right and left overbanks. The overbank segments can be further subdivided depending on the conditions. Manning’s n values can vary with depth of water within a segment… Standard textbooks and hydraulic references such as Brater and King (1976) and various NRCS and USGS books provide examples of Manning’s n values in constructed and natural channels." <ref name ="NRCS">[[National Engineering Handbook: Chapter 14 - Stage Discharge Relations | National Engineering Handbook: Chapter 14 - Stage Discharge Relations, NRCS, 2012]]</ref>.
 
“Standard textbooks and hydraulic [[references]] such as Brater and King (1976) and various NRCS and USGS books provide examples of Manning’s n values in constructed and natural channels. The refence section lists some of the available Manning’s n values references, such as [[U.S. Geological Survey]] (1967), Aldridge and Garrett (1973), U.S. Geological [[Survey]] (1989a) U.S. Army Corps. Of Engineers (USACE 2010b, Chow (1959), and Yochum (2010). Appendix A gives a procedure for estimating Manning’s n values in natural streams, floodways, and similar streams (Cowan 1956)”. <ref name ="NRCS">[[National Engineering Handbook: Chapter 14 - Stage Discharge Relations | National Engineering Handbook: Chapter 14 - Stage Discharge Relations, NRCS, 2012]]</ref>.


==Best Practices Resources==
==Best Practices Resources==

Revision as of 22:42, 13 December 2022


The three most common methods of computing friction effects fluid flow are the Chezy equation, the Darcy-Weisbach equation, and the Manning equation. For open channel flow, the Manning equation is the most common method used.

“The selection of Manning’s n values is important in the computation of water surface profiles and flow in open channels. The selected values should be representative of flow conditions at the cross section location. The cross section can be subdivided into several segments to properly represent the resistance to flow within a cross section. Normally, a natural cross section is subdivided into three segments: channel, right and left overbanks. The overbank segments can be further subdivided depending on the conditions. Manning’s n values can vary with depth of water within a segment… Standard textbooks and hydraulic references such as Brater and King (1976) and various NRCS and USGS books provide examples of Manning’s n values in constructed and natural channels." [1].

Best Practices Resources

National Engineering Handbook: Chapter 14 - Stage Discharge Relations (Natural Resources Conservation Service)


Citations:


Revision ID: 5486
Revision Date: 12/13/2022