n_maynord1991 {HYDROCAL}

Compute grain roughness following Maynord (1991)

Description

n_maynord1991 calculate Manning's n using the Maynord (1991) method of estimating grain roughness

Usage

n_maynord1991(grain, restrict = TRUE)

Arguments

grain

grain size (d90) in millimeters. The original model was calibrated for 4.57 mm < d90 < 134 mm.

restrict

allows for function parameters to restrict certain values. Type bool. Default TRUE.

Value

Manning's n

References

Maynord, S. T. 1991. Flow Resistance of Riprap. Journal of Hydraulic Engineering. American Society of Civil Engineers, Vol. 117 (6), pp. 687-696.

Examples

# Result: Manning's n of 0.030
n_maynord1991(100)

# Result: Manning's n of 0.018
n_maynord1991(5)

# Result: Manning's n of 0.027
n_maynord1991(50)

# Result: Manning's n of Grain must be within 4.57 and 134 mm.
n_maynord1991(1)