Convert observed flight flux to number of flights through turbine plane (i.e. interactions).

Usage

turbine_flights(obs_flux, rotor_diameter, hub_height)

Arguments

obs_flux: numeric; number of flights through one unit area of vertical space per unit time as output by obs_flux() or similar
rotor_diameter: numeric; rotor diameter. Must be in the equivalent units to the unit area of obs_flux (i.e., if the obs_flux is per m\(^2\), rotor_diameter must be in m).
hub_height: numeric; hub height. Must be in the equivalent units to the unit area of obs_flux (i.e., if the obs_flux is per m\(^2\), hub_height must be in m).

Value

numeric; number of flights through turbine plane per unit time. The turbine plane is a rectangle defined by the rotor diameter and tip height of the turbine. Time interval is the same as referenced by obs_flux input.

Details

Scale to turbine

turbine_flights() converts the flight flux through one unit area of vertical space into the number of flights through an arbitrary vertical plane of width equal to rotor diameter and height equal to the tip height of the turbine.

The time interval is not adjusted (i.e. if you input flights / min, it will output flights / min).

Examples


## A simple example of calculating flux from a point count and
## using this to generate the number of flights through a turbine 
## in a year
## 
## # Step by step
## 

df_obs <- data.frame(size = c(0, 2 , 3, 0), # four surveys
                     survey_duration = c(20, 20, 18, 20), # minutes
                     # Optional survey weights to deal with stratification etc
                     survey_weight = c(1,1,1,1))

rotor_diameter <- 300
hub_height <- 200
edr <- 800 # derive from distance model
mean_h <- 60 # derive from height distribution

# flights observed per minute of survey
flights_per_min <- encounter_rate(
  df_obs_summary = df_obs,
  wilson_correction = TRUE # Default
)

# observed flights through vertical plane of one metre squared in one minute
flights_per_m2_per_min <- obs_flux(
  encounter_rate = flights_per_min,
  eff_detection_width = 2*edr,
  mean_flight_height = mean_h
)

# scale to turbine width and height
flights_turbine_min <- turbine_flights(
  obs_flux = flights_per_m2_per_min,
  rotor_diameter = rotor_diameter,
  hub_height = hub_height
)

# scale to annual flights through area of rotor_diameter x turbine height 
flights_turbine_year <- flights_per_year(
  flights_per_time = flights_turbine_min,
  time_units = "min", # Default
  prop_day = 0.5,  #diurnal species
  prop_year = 1    # present all year
)

## Alternate calc using a wrapper function
## to go from observations to turbine flights per year
## 
flights_turbine_year2 <- turbine_flights_year(
  survey_type = "point", # only supported option currently
  encounter_rate = flights_per_min,
  time_units = "min",
  eff_detection_width = 2*edr,
  mean_flight_height = mean_h,
  rotor_diameter = rotor_diameter,
  hub_height = hub_height,
  prop_day = 0.5,  #diurnal species
  prop_year = 1   # present all year
)

#They are the same
flights_turbine_year
#> [1] 9219.05
flights_turbine_year2
#> [1] 9219.05