Model VSM LLT

Enumeration of the implemented model types.

Elements

• VSM: Vortex Step Method
• LLT: Lifting Line Theory

AeroModel LEI_AIRFOIL_BREUKELS POLAR_VECTORS POLAR_MATRICES INVISCID

Enumeration of the implemented aerodynamic models. See also: AeroData

Elements

• LEI_AIRFOIL_BREUKELS: Polynom approximation for leading edge inflatable kites
• POLAR_VECTORS: Polar vectors as function of alpha (lookup tables with interpolation)
• POLAR_MATRICES: Polar matrices as function of alpha and beta (lookup tables with interpolation)
• INVISCID

where alpha is the angle of attack, beta is trailing edge angle.

PanelDistribution LINEAR COSINE COSINE_VAN_GARREL SPLIT_PROVIDED UNCHANGED

Enumeration of the implemented panel distributions.

Elements

• LINEAR # Linear distribution
• COSINE # Cosine distribution
• COSINE_VAN_GARREL # van Garrel cosine distribution
• SPLIT_PROVIDED # Split provided sections
• UNCHANGED # Keep original sections

InitialGammaDistribution ELLIPTIC ZEROS

Enumeration of the implemented initial gamma distributions.

Elements

• ELLIPTIC
• ZEROS

SolverStatus FEASIBLE INFEASIBLE FAILURE

Enumeration to report back the validity of the result of the solve! function. Used in the VSMSolution struct.

Elements

• FEASIBLE: The gamma distribution is physically feasible
• INFEASIBLE: The gamma distribution is physically infeasible
• FAILURE: The result did not converge within the maximal number of iterations

const MVec3 = MVector{3, Float64}

Basic 3-dimensional vector, stack allocated, mutable.

const PosVector=Union{MVec3, Vector}

Position vector, either a MVec3 or a Vector for use in function signatures.

const VelVector=Union{MVec3, Vector}

Velocity vector, either a MVec3 or a Vector for use in function signatures.

AeroData= Union{
    Nothing,
    NTuple{2, Float64},
    Tuple{Vector{Float64}, Vector{Float64}, Vector{Float64}, Vector{Float64}},
    Tuple{Vector{Float64}, Vector{Float64}, Matrix{Float64}, Matrix{Float64}, Matrix{Float64}}
}

Union of different definitions of the aerodynamic properties of a wing section. See also: AeroModel

• nothing for INVISCID
• (tube_diameter, camber) for LEI_AIRFOIL_BREUKELS
• (alpha_range, cl_vector, cd_vector, cm_vector) for POLAR_VECTORS
• (alpha_range, beta_range, cl_matrix, cd_matrix, cm_matrix) for POLAR_MATRICES

where alpha is the angle of attack [rad], beta is trailing edge angle [rad], cl the lift coefficient, cd the drag coefficient and cm the pitching moment coefficient. The camber of a kite refers to the curvature of its airfoil shape. The camber is typically measured as the maximum distance between the mean camber line (the line equidistant from the upper and lower surfaces) and the chord line of the airfoil.

mutable struct Section

Represents a wing section with leading edge, trailing edge, and aerodynamic properties.

Fields

• LE_point::MVec3 = zeros(MVec3): Leading edge point coordinates
• TE_point::MVec3 = zeros(MVec3): Trailing edge point coordinates
• aero_model::AeroModel = INVISCID: AeroModel
• aero_data::AeroData = nothing: See: [AeroData]

Section(LE_point::Vector{Float64}, TE_point::Vector{Float64}, 
        aero_model=INVISCID, aero_data=nothing)

Constructor for Section that allows to pass Vectors of Float64 as point coordinates.

Wing

Represents a wing composed of multiple sections with aerodynamic properties.

Fields

• n_panels::Int64: Number of panels in aerodynamic mesh
• spanwise_panel_distribution::PanelDistribution: PanelDistribution
• spanwise_direction::MVec3: Wing span direction vector
• sections::Vector{Section}: Vector of wing sections, see: Section
• refined_sections::Vector{Section}: Vector of refined wing sections, see: Section
• remove_nan::Bool: Wether to remove the NaNs from interpolations or not

Wing(n_panels::Int;
     spanwise_panel_distribution::PanelDistribution=LINEAR,
     spanwise_direction::PosVector=MVec3([0.0, 1.0, 0.0]),
     remove_nan::Bool=true)

Constructor for a Wing struct with default values that initializes the sections and refined sections as empty arrays.

Parameters

• n_panels::Int64: Number of panels in aerodynamic mesh
• spanwise_panel_distribution::PanelDistribution = LINEAR: PanelDistribution
• spanwise_direction::MVec3 = MVec3([0.0, 1.0, 0.0]): Wing span direction vector
• remove_nan::Bool: Wether to remove the NaNs from interpolations or not

KiteWing

Represents a curved wing that inherits from Wing with additional geometric properties.

Fields

• All fields from Wing:
  • n_panels::Int64: Number of panels in aerodynamic mesh
  • spanwise_panel_distribution::PanelDistribution: see: PanelDistribution
  • spanwise_direction::MVec3: Wing span direction vector
  • sections::Vector{Section}: List of wing sections, see: Section
  • refined_sections::Vector{Section}
  • remove_nan::Bool: Wether to remove the NaNs from interpolations or not
• Additional fields:
  • circle_center_z::Vector{Float64}: Center of circle coordinates
  • gamma_tip::Float64: Angle between the body frame z axis and the vector going from the kite circular shape center to the wing tip.
  • inertia_tensor::Matrix{Float64}: see: calculate_inertia_tensor
  • radius::Float64: Radius of curvature
  • le_interp::NTuple{3, Extrapolation}: see: Extrapolation
  • te_interp::NTuple{3, Extrapolation}
  • area_interp::Extrapolation

KiteWing(obj_path, dat_path; alpha=0.0, crease_frac=0.75, wind_vel=10., mass=1.0, 
         n_panels=54, n_sections=n_panels+1, spanwise_panel_distribution=UNCHANGED, 
         spanwise_direction=[0.0, 1.0, 0.0], remove_nan::Bool=true)

Constructor for a KiteWing that allows to use an .obj and a .dat file as input.

Parameters

• obj_path: Path to the .obj file used for creating the geometry
• dat_path: Path to the .dat file, a standard format for 2d foil geometry

Keyword Parameters

• alpha=0.0: Angle of attack of each segment relative to the x axis [rad]
• crease_frac=0.75: The x coordinate around which the trailing edge rotates on a normalized 2d foil, used in the xfoil polar generation
• wind_vel=10.0: Apparent wind speed in m/s, used in the xfoil polar generation
• mass=1.0: Mass of the wing in kg, used for the inertia calculations
• n_panels=54: Number of panels.
• n_sections=n_panels+1: Number of sections (there is a section on each side of each panel.)
• spanwise_panel_distribution=UNCHANGED: see: PanelDistribution
• spanwise_direction=[0.0, 1.0, 0.0]
• remove_nan::Bool: Wether to remove the NaNs from interpolations or not

@with_kw mutable struct BodyAerodynamics{P}

Main structure for calculating aerodynamic properties of bodies.

Fields

• panels::Vector{Panel}: Vector of Panel structs
• wings::Vector{AbstractWing}: A vector of wings; a body can have multiple wings
• _va::MVec3 = zeros(MVec3): A vector of the apparent wind speed, see: MVec3
• omega::MVec3 = zeros(MVec3): A vector of the turn rates around the kite body axes
• gamma_distribution::Vector{Float64}=zeros(Float64, P): A vector of the circulation of the velocity field; Length: Number of segments. [m²/s]
• alpha_uncorrected::Vector{Float64}=zeros(Float64, P): unclear, please define
• alpha_corrected::Vector{Float64}=zeros(Float64, P): unclear, please define
• stall_angle_list::Vector{Float64}=zeros(Float64, P): unclear, please define
• alpha_array::Vector{Float64} = zeros(Float64, P)
• vaarray::Vector{Float64} = zeros(Float64, P)
• workvectors::NTuple{10,MVec3} = ntuple( -> zeros(MVec3), 10)
• AIC::Array{Float64, 3} = zeros(3, P, P)
• projected_area::Float64 = 1.0: The area projected onto the xy-plane of the kite body reference frame [m²]

Solver

Main solver structure for the Vortex Step Method.See also: solve

Attributes

General settings

• aerodynamic_model_type::Model = VSM: The model type, see: Model
• density::Float64 = 1.225: Air density [kg/m³]
• max_iterations::Int64 = 1500
• allowed_error::Float64 = 1e-5: relative error
• tol_reference_error::Float64 = 0.001
• relaxation_factor::Float64 = 0.03: Relaxation factor for convergence

Damping settings

• is_with_artificial_damping::Bool = false: Whether to apply artificial damping
• artificial_damping::NamedTuple{(:k2, :k4), Tuple{Float64, Float64}} = (k2=0.1, k4=0.0): Artificial damping parameters

Additional settings

• type_initial_gamma_distribution::InitialGammaDistribution = ELLIPTIC: see: InitialGammaDistribution
• core_radius_fraction::Float64 = 1e-20:
• mu::Float64 = 1.81e-5: Dynamic viscosity [N·s/m²]
• is_only_f_and_gamma_output::Bool = false: Whether to only output f and gamma

Solution

sol::VSMSolution = VSMSolution(): The result of calling solve!

VSMSolution

Struct for storing the solution of the solve! function. Must contain all info needed by KiteModels.jl.

Attributes

• gamma_distribution::Union{Nothing, Vector{Float64}}: Vector containing the panel circulations
• aero_force::MVec3: Aerodynamic force vector in KB reference frame [N]
• aero_moments::MVec3: Aerodynamic moments [Mx, My, Mz] around the reference point [Nm]
• force_coefficients::MVec3: Aerodynamic force coefficients [CFx, CFy, CFz] [-]
• moment_coefficients::MVec3: Aerodynamic moment coefficients [CMx, CMy, CMz] [-]
• moment_distribution::Vector{Float64}: Pitching moments around the spanwise vector of each panel. [Nm]
• momentcoefficientdistribution::Vector{Float64}: Pitching moment coefficient around the spanwise vector of each panel. [-]
• solver_status::SolverStatus: enum, see SolverStatus