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Introduction

Most functions need an instance of the struct AtmosphericModel as first parameter, which can be created using the following code:

using AtmosphericModels, KiteUtils

set_data_path("data")
set = load_settings("system.yaml"; relax=true)
am::AtmosphericModel = AtmosphericModel(set)

This requires that the files system.yaml and settings.yaml exist in the folder data. See also Settings. The parameter relax=true allows loading a yaml file that does not contain all sections needed to run a kite power system simulation. This is useful if you want to use this package for other purposes than simulating kite power systems.

Types

Exported types

AtmosphericModels.AtmosphericModel — Type
mutable struct AtmosphericModel

Struct that is storing the settings and the state of the atmosphere.

Fields

  • set::Settings: The Settings struct
  • rho_zero_temp
  • wf::Union{WindField, Nothing}: The 3D WindField or nothing
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AtmosphericModels.AtmosphericModel — Method
AtmosphericModel(set::Settings; nowindfield::Bool=false)

Constructs an AtmosphericModel using the provided Settings.

Arguments

  • set::Settings: The settings object containing configuration parameters for the atmospheric model.
  • nowindfield::Bool=false: Optional keyword argument. If true, the wind field will not be loaded.

Returns

  • An instance of AtmosphericModel configured according to the provided settings.
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Private types

AtmosphericModels.WindField — Type
struct WindField

Struct that is storing a 3D model of wind vectors of the atmosphere. The Fields x, y and z store the grid coordinates, the fields u, v and w the wind turbulence vectors.

Fields

  • x_max::Float64 = NaN
  • x_min::Float64 = NaN
  • y_max::Float64 = NaN
  • y_min::Float64 = NaN
  • z_max::Float64 = NaN
  • z_min::Float64 = NaN
  • last_speed::Float64 = 0.0
  • valid::Bool = false
  • x::Union{SRL, Array{Float64, 3}}
  • y::Union{SRL, Array{Float64, 3}}
  • z::Union{SRL, Array{Float64, 3}}
  • u::Array{Float64, 3}
  • v::Array{Float64, 3}
  • w::Array{Float64, 3}
  • param::Vector{Float64} = [0, 0] # [alpha, v_wind_gnd]
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Functions

Wind shear and air density calculation

AtmosphericModels.calc_rho — Function
calc_rho(s::AM, height)

Calculates the air density at a given height above ground level.

Arguments

  • s::AM: An instance of the AM (Atmospheric Model) struct containing atmospheric parameters.
  • height: The height above ground level (in meters) at which to calculate the air density.

Returns

  • The air density at the specified height (in kg/m³).

Notes

  • The calculation assumes an exponential decrease of air density with altitude.
  • s.rho_zero_temp is the reference air density at ground level.
  • s.set.height_gnd is the ground height offset.
  • The scale height used is 8550.0 meters.
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AtmosphericModels.calc_wind_factor — Function
calc_wind_factor(am::AM, height; profile_law::Int64=am.set.profile_law)

Calculates the wind factor at a given height using the specified wind profile law.

Arguments

  • am::AM: An instance of the AM type containing atmospheric model parameters.
  • height: The height (in meters) at which to calculate the wind factor.
  • profile_law::Int64: (Optional) The wind profile law to use for the calculation. Defaults to am.set.profile_law.

Returns

  • The wind factor at the specified height as determined by the chosen profile law.
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Wind turbulence calculation

AtmosphericModels.get_wind — Function
get_wind(am::AtmosphericModel, x, y, z, t; upwind_dir=0.0, interpolate=false)

Returns the wind vector at the specified position (x, y, z) and time t using the given AtmosphericModel (am).

Uses Taylor's frozen-turbulence hypothesis: the field is advected along the mean wind direction. The position is first rotated into the wind-aligned frame so that:

  • the along-wind component (+ time advection) maps to the long field dimension (y, e.g. 4050 m), avoiding short-period repetition during long simulations.
  • the cross-wind component maps to the short field dimension (x, e.g. 100 m).

Arguments

  • am::AtmosphericModel: The atmospheric model providing environmental parameters.
  • x, y, z: Position in the simulation (ENU) frame where the wind is evaluated. [m]
  • t: Current simulation time. [s]
  • upwind_dir (optional, default = 0.0): Direction the wind is coming FROM [rad]. Zero is north, clockwise positive (same convention as in calc_turbulent_wind).
  • interpolate (optional, default = false): If true, interpolate wind values between grid points; otherwise, use nearest-grid-point values.

Returns

  • A tuple (v_x, v_y, v_z) representing the wind velocity in the wind-aligned frame [m/s], where v_x is the along-wind component (includes mean wind), v_y is cross-wind, v_z is vertical.
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AtmosphericModels.rel_turbo — Function
rel_turbo(am::AtmosphericModel, v_wind = am.set.v_wind)

Find the closest relative turbulence value for a given ground wind speed.

Arguments

  • am::AtmosphericModel: The atmospheric model instance containing relevant parameters.
  • v_wind: (Optional) The wind velocity to use for the calculation. Defaults to am.set.v_wind.

Returns

  • The computed relative turbulence value.
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AtmosphericModels.new_windfield — Function
new_windfield(am::AtmosphericModel, v_wind_gnd; prn=true)

Create a new wind field file using the given, scalar ground wind velocity v_wind_gnd.

Parameters

  • am::AtmosphericModel: The atmospheric model for which the wind field is created.
  • v_wind_gnd: A scalar representing the wind velocity at ground level.
  • prn: Optional boolean flag to control printing of progress messages (default is true).

Returns

  • nothing
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AtmosphericModels.new_windfields — Function
new_windfields(am::AtmosphericModel; prn=true)

Create and initialize new wind fields for all ground wind speeds, defined in am.set.v_wind_gnds and save them for the given AtmosphericModel instance am.

Arguments

  • am::AtmosphericModel: The atmospheric model for which wind fields are to be generated.
  • prn: Optional boolean flag to control printing of progress messages (default is true).

Returns

  • nothing
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