Calculates the frictional resistance coefficient (Cf) (dimensionless).

calcCf(shipSpeed, lwl, seawaterTemp = 15, seawaterDensity = 1.025)

Arguments

shipSpeed

Ship actual speed (vector of numericals, m/s) (see calcSpeedUnitConversion)

lwl

Waterline length (vector of numericals, m) (see calclwl)

seawaterTemp

Sea water temperature. Default = 15 (degrees Celsius). Can supply either a vector of numericals, a single number, or rely on the default

seawaterDensity

Sea water density. Default = 1.025 (g/cm^3). Can supply either a vector of numericals, a single number, or rely on the default

Value

Cf (vector of numericals, dimensionless)

Details

Calculates frictional resistance coefficient using the International Tank Towing Committee (ITTC) 1957 method where: $$Cf = \frac{0.075}{(log(V*Lwl/visc)-2)^2}$$

References

Kristensen, H. O. and Lutzen, M. 2013. "Prediction of Resistance and Propulsion Power of Ships."

See also

Examples

calcCf(seq(1,5,1), 218.75, 15, 1.025)
#> [1] 0.001910808 0.001739616 0.001649932 0.001590441 0.001546485