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Estimate pipe friction factor with Vatankhah formula

Source: R/fric_vatankhan.R
fric_vatankhan.Rd

Estimate Darcy friction factor explicitly with extremely accurate Vatankhah-Kouchakzadeh approximation of Colebrook equation.

Usage

fric_vatankhan(reynolds, roughness = 0, strict = FALSE)

Arguments

reynolds

Reynolds number, []. Type: assert_double.

roughness

relative roughness, []. Type: assert_double.

strict

calculate only inside the precision region. Type: assert_flag.

Value

Pipe friction factor, []. Type: assert_double.

Details

Vatankhah's formula is reported to be extremely accurate in the region:

  • 5.0e3 <= reynolds <= 1.0e8

  • 1e-6 <= roughness <= 0.05

In strict = TRUE mode argument values outside this precision region are not allowed, whereas in strict = FALSE either NAs are generated in that case or calculation for laminar flow is performed when reynolds < 2100.0.

References

  1. Offor, U. and Alabi, S. (2016) An Accurate and Computationally Efficient Explicit Friction Factor Model.Advances in Chemical Engineering and Science, 6, pp. 237-245. doi:10.4236/aces.2016.63024 .

  2. Ali R. Vatankhah, Salah Kouchakzadeh (2009) Exact equations for pipe-flow problems.Journal of Hydraulic Research, 47:4, pp. 537-538, doi:10.1080/00221686.2009.9522031 .

See also

Other Fluid properties: fric_buzzelli(), fric_romeo(), re_u()

Examples

library(pipenostics)

fric_vatankhan(c(2118517, 2000, 2118517), c(1e-6, 70e-3/1, 7e-3/1))
#> [1] 0.01031665 0.03200000 0.03375210

fric_vatankhan(c(2118517, 5500, 2118517), c(1e-6, 50e-3/1, 7e-3/1), TRUE)
#> [1] 0.01031665 0.07556163 0.03375210