Skip to contents

Returns the flux factor, expressing the total number of bird flights through the rotors of the wind farm per month if all flights occurred within the rotor's circle area of all turbines, i.e. before the proportion at risk height and avoidance level are taken into account.

Usage

get_flux_factor(
  n_turbines,
  rotor_radius,
  flight_speed,
  bird_dens,
  daynight_hrs,
  noct_activity
)

Arguments

n_turbines

An integer, the number of turbines on the wind farm (\(T\)).

rotor_radius

A numeric value, the radius of the rotor (\(R\)), in metres.

flight_speed

A numeric value, the bird flight speed (\(v\)), in metres/sec.

bird_dens

A numeric vector with daytime in-flight bird densities (\(D_A\)), for each month, in birds/km^2.

daynight_hrs

A data frame with the total number of daylight hours and night hours at the wind farm site's location, in each month. It must contain, at least, the following columns:

  • Month, name of the month.

  • Day, daylight duration, in decimal hours.

  • Night, night time duration, in decimal hour

noct_activity

A numeric value. The nocturnal flight activity level, expressed as a proportion of daytime activity levels (\(f_night\)).

Value

The number of bird flights potentially transiting through rotors at each time period (assuming no avoidance), if all flights occur within the rotor's circular area.

Details

The flux factor is used for other model calculations. Methodology and assumptions underpinning get_flux_factor are described in "Stage B" of Band (2012)

Examples

  get_flux_factor(
      n_turbines = 100,
      rotor_radius = 120,
      flight_speed = 13.1,
      bird_dens = c(1.19,0.85,1.05,1.45,1.41,1.45,1.12,1.45,0.93,0.902,1.06,1.23),
      daynight_hrs = Day_Length(52),
      noct_activity = 0.5
      )
#>  [1] 530055.8 358508.1 518368.7 731968.6 770303.2 785694.9 620622.8 772488.3
#>  [9] 455350.9 431349.1 464701.3 539745.3