iemisc (version 0.5.0)

nc3: Lotter method for composite Manning's n

Description

This function computes the composite Manning's n using the Lotter method.

Usage

nc3(P, n, R)

Arguments

P

numeric vector that contains "wetted perimeter of any section i"

n

numeric vector that contains "Manning's n of any section i"

R

numeric vector that contains "hydraulic radius of any section i"

Value

• numeric vector that contains nc3 as Manning's composite n.

encoding

UTF-8

Details

"A composite value of Manning's n for a single channel; that is, for the main channel only of a compound channel or a canal with laterally varying roughness."

The equation to find Manning's composite n using the Lotter method is

$$n_c = \frac{PR^\frac{5}{3}}{\sum \limits_{i=1}^N \frac{P_i R_i^\frac{5}{3}}{n_i}}$$

[object Object],[object Object],[object Object],[object Object],[object Object],[object Object],[object Object]

References

1. Terry W. Sturm,Open Channel Hydraulics, 2nd Edition, New York City, New York: The McGraw-Hill Companies, Inc., 2010, page 118-119.

See Also

n for Manning's n for natural channels, nc1 for Horton method for composite Manning's n, nc2 for Einstein and Banks method for composite Manning's n, and nc4 for Krishnamurthy and Christensen method for composite Manning's n.

Examples

library(iemisc)
nc3(n = c(0.0024, 0.035), P = c(23.65, 36.08), R = c(2.02, 6.23))