# Creates a system curve for a piping system using the static head and a coefficient.

Source:`R/systemcurve.R`

`systemcurve.Rd`

Creates a system curve for a piping system using the static head and a coefficient.

## Usage

`systemcurve(hs = NULL, K = NULL, units = c("SI", "Eng"))`

## Arguments

- hs
Numeric value of the static head [\(m\) or \(ft\)]

- K
Numeric value of the coefficient in the equation \(h = hs + {K}{Q}^2\) where Q has units of \(m^3 s^{-1}\) or \(ft^3 s^{-1}\)

- units
character vector that contains the system of units [options are

`SI`

for International System of Units and`Eng`

for English (US customary) units.

## Value

Returns an object of class `systemcurve`

consisting of a list including:

curve - a function defining the system curve

eqn - a character vector of the equation for the curve

units - the units system passed to the function

## Examples

```
#Input in Eng units. Coefficient can be calculated manually or using
#other package functions for friction loss in a pipe system using \eqn{Q=1}
ans <- darcyweisbach(Q = 1,D = 20/12, L = 3884, ks = 0.0005, nu = 1.23e-5, units = "Eng")
#> hf missing: solving a Type 1 problem
systemcurve(hs = 30, K = ans$hf, units = "Eng")
#> $curve
#> function (x)
#> hs + x^2 * K
#> <bytecode: 0x557060008cd0>
#> <environment: 0x557060008790>
#>
#> $eqn
#> [1] "h == 30 + 0.16*Q^2"
#>
#> $units
#> [1] "Eng"
#>
#> attr(,"class")
#> [1] "systemcurve"
```