Change alpha beta to theta delta

examples/ram_air_kite.jl

@@ -12,8 +12,8 @@ body_aero = BodyAerodynamics([wing];)
 
 if DEFORM
     alpha = [deg2rad(10), 0]
-    beta = [deg2rad(10), 0]
-    @time VortexStepMethod.deform!(wing, alpha, beta; width=1.0)
+    delta = [deg2rad(10), 0]
+    @time VortexStepMethod.deform!(wing, alpha, delta; width=1.0)
     @time VortexStepMethod.init!(body_aero)
 end
 
@@ -62,7 +62,7 @@ PLOT && plot_distribution(
     [body_y_coordinates],
     [results],
     ["VSM"];
-    title="CAD_spanwise_distributions_alpha_$(round(aoa, digits=1))_beta_$(round(side_slip, digits=1))_yaw_$(round(yaw_rate, digits=1))_v_a_$(round(v_a, digits=1))",
+    title="CAD_spanwise_distributions_alpha_$(round(aoa, digits=1))_delta_$(round(side_slip, digits=1))_yaw_$(round(yaw_rate, digits=1))_v_a_$(round(v_a, digits=1))",
     data_type=".pdf",
     is_save=false,
     is_show=true,

examples/stall_model.jl

@@ -91,7 +91,7 @@ PLOT && plot_distribution(
     [CAD_y_coordinates, CAD_y_coordinates],
     [results, results_with_stall],
     ["VSM", "VSM with stall correction"];
-    title="CAD_spanwise_distributions_alpha_$(round(aoa, digits=1))_beta_$(round(side_slip, digits=1))_yaw_$(round(yaw_rate, digits=1))_v_a_$(round(v_a, digits=1))",
+    title="CAD_spanwise_distributions_alpha_$(round(aoa, digits=1))_delta_$(round(side_slip, digits=1))_yaw_$(round(yaw_rate, digits=1))_v_a_$(round(v_a, digits=1))",
     data_type=".pdf",
     save_path=joinpath(save_folder, "spanwise_distributions"),
     is_save=false,

src/VortexStepMethod.jl

@@ -83,10 +83,10 @@ Enumeration of the implemented aerodynamic models. See also: [AeroData](@ref)
 # 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)
+- `POLAR_MATRICES`: Polar matrices as function of alpha and delta (lookup tables with interpolation)
 - INVISCID
 
-where `alpha` is the angle of attack, `beta` is trailing edge angle.
+where `alpha` is the angle of attack, `delta` is trailing edge angle.
 """
 @enum AeroModel begin
    LEI_AIRFOIL_BREUKELS
@@ -153,9 +153,9 @@ Union of different definitions of the aerodynamic properties of a wing section.
   - 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` 
+  - (`alpha_range`, `delta_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,
+where `alpha` is the angle of attack [rad], `delta` 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) 

src/body_aerodynamics.jl

@@ -113,9 +113,9 @@ function init!(body_aero::BodyAerodynamics;
         # Create panels
         for i in 1:wing.n_panels
             if wing isa RamAirWing
-                beta = wing.beta_dist[i]
+                delta = wing.delta_dist[i]
             else
-                beta = 0.0
+                delta = 0.0
             end
             init!(
                 body_aero.panels[idx], 
@@ -128,7 +128,7 @@ function init!(body_aero::BodyAerodynamics;
                 panel_props.x_airf[i],
                 panel_props.y_airf[i],
                 panel_props.z_airf[i],
-                beta;
+                delta;
                 remove_nan=wing.remove_nan
             )
             idx += 1

src/kite_geometry.jl

@@ -338,7 +338,7 @@
     te_interp::NTuple{3, Extrapolation}
     area_interp::Extrapolation
     alpha_dist::Vector{Float64}
-    beta_dist::Vector{Float64}
+    delta_dist::Vector{Float64}
 end
 
 """
@@ -401,7 +401,7 @@
     end
 
     @info "Loading polars and kite info from $polar_path and $info_path"
-    (alpha_range, beta_range, cl_matrix::Matrix, cd_matrix::Matrix, cm_matrix::Matrix) = deserialize(polar_path)
+    (alpha_range, delta_range, cl_matrix::Matrix, cd_matrix::Matrix, cm_matrix::Matrix) = deserialize(polar_path)
     if remove_nan
         interpolate_matrix_nans!(cl_matrix)
         interpolate_matrix_nans!(cd_matrix)
@@ -414,7 +414,7 @@
     # Create sections
     sections = Section[]
     for gamma in range(-gamma_tip, gamma_tip, n_sections)
-        aero_data = (collect(alpha_range), collect(beta_range), cl_matrix, cd_matrix, cm_matrix)
+        aero_data = (collect(alpha_range), collect(delta_range), cl_matrix, cd_matrix, cm_matrix)
         LE_point = [le_interp[i](gamma) for i in 1:3]
         TE_point = [te_interp[i](gamma) for i in 1:3]
         push!(sections, Section(LE_point, TE_point, POLAR_MATRICES, aero_data))
@@ -426,20 +426,20 @@
 end
 
 """
-    deform!(wing::RamAirWing, alphas::AbstractVector, betas::AbstractVector; width)
+    deform!(wing::RamAirWing, alphas::AbstractVector, deltas::AbstractVector; width)
 
-Deform wing by applying left and right alpha and beta.
+Deform wing by applying left and right alpha and delta.
 
 # Arguments
 - `wing`: RamAirWing to deform
 - `alphas`: [left, right] the angle between of the kite and the body x-axis in radians
-- `betas`: [left, right] the deformation of the trailing edges
+- `deltas`: [left, right] the deformation of the trailing edges
 - `width`: Transition width in meters to smoothe out the transition from left to right deformation
 
 # Effects
 Updates wing.sections with deformed geometry
 """
-function deform!(wing::RamAirWing, alphas::AbstractVector, betas::AbstractVector; width)
+function deform!(wing::RamAirWing, alphas::AbstractVector, deltas::AbstractVector; width)
     local_y = zeros(MVec3)
     chord = zeros(MVec3)
 
@@ -452,12 +452,12 @@
         else
             alphas[1] * (1.0 - normalized_gamma) + alphas[2] * normalized_gamma
         end
-        wing.beta_dist[i] = if normalized_gamma <= 0.0
-            betas[1]
+        wing.delta_dist[i] = if normalized_gamma <= 0.0
+            deltas[1]
         elseif normalized_gamma >= 1.0
-            betas[2]
+            deltas[2]
         else
-            betas[1] * (1.0 - normalized_gamma) + betas[2] * normalized_gamma
+            deltas[1] * (1.0 - normalized_gamma) + deltas[2] * normalized_gamma
         end
 
         section1 = wing.non_deformed_sections[i]

src/panel.jl

@@ -70,7 +70,7 @@
         SemiInfiniteFilament(),
         SemiInfiniteFilament()
     )
-    beta::Float64 = 0.0
+    delta::Float64 = 0.0
 end
 
 function init_pos!(
@@ -84,7 +84,7 @@
     x_airf::PosVector,
     y_airf::PosVector,
     z_airf::PosVector,
-    beta
+    delta
 )
     # Initialize basic geometry
     panel.TE_point_1 .= section_1.TE_point
@@ -108,7 +108,7 @@
     panel.x_airf .= x_airf
     panel.y_airf .= y_airf
     panel.z_airf .= z_airf
-    panel.beta = Float64(beta)
+    panel.delta = Float64(delta)
     return nothing
 end
 
@@ -157,19 +157,19 @@
 
         elseif panel.aero_model == POLAR_MATRICES
             !all(isapprox.(aero_1[1], aero_2[1])) && @error "Make sure you use the same alpha range for all your interpolations."
-            !all(isapprox.(aero_1[2], aero_2[2])) && @error "Make sure you use the same beta range for all your interpolations."
+            !all(isapprox.(aero_1[2], aero_2[2])) && @error "Make sure you use the same delta range for all your interpolations."
 
             polar_data = (
                 Matrix{Float64}((aero_1[3] + aero_2[3]) / 2),
                 Matrix{Float64}((aero_1[4] + aero_2[4]) / 2),
                 Matrix{Float64}((aero_1[5] + aero_2[5]) / 2)
             )
             alphas = Vector{Float64}(aero_1[1])
-            betas = Vector{Float64}(aero_1[2])
+            deltas = Vector{Float64}(aero_1[2])
 
-            panel.cl_interp = linear_interpolation((alphas, betas), polar_data[1]; extrapolation_bc)
-            panel.cd_interp = linear_interpolation((alphas, betas), polar_data[2]; extrapolation_bc)
-            panel.cm_interp = linear_interpolation((alphas, betas), polar_data[3]; extrapolation_bc)
+            panel.cl_interp = linear_interpolation((alphas, deltas), polar_data[1]; extrapolation_bc)
+            panel.cd_interp = linear_interpolation((alphas, deltas), polar_data[2]; extrapolation_bc)
+            panel.cm_interp = linear_interpolation((alphas, deltas), polar_data[3]; extrapolation_bc)
         else
             throw(ArgumentError("Polar data in wrong format: $aero_1"))
         end
@@ -190,12 +190,12 @@
     x_airf::PosVector,
     y_airf::PosVector,
     z_airf::PosVector,
-    beta;
+    delta;
     init_aero = true,
     remove_nan = true
 )
     init_pos!(panel, section_1, section_2, aero_center, control_point, bound_point_1, bound_point_2,
-        x_airf, y_airf, z_airf, beta)
+        x_airf, y_airf, z_airf, delta)
     init_aero && init_aero!(panel, section_1, section_2; remove_nan)
     return nothing
 end
@@ -331,7 +331,7 @@
     elseif panel.aero_model == POLAR_VECTORS
         cl = panel.cl_interp(alpha)::Float64
     elseif panel.aero_model == POLAR_MATRICES
-        cl = panel.cl_interp(alpha, panel.beta)::Float64
+        cl = panel.cl_interp(alpha, panel.delta)::Float64
     else
         throw(ArgumentError("Unsupported aero model: $(panel.aero_model)"))
     end
@@ -356,8 +356,8 @@
         cd = panel.cd_interp(alpha)::Float64
         cm = panel.cm_interp(alpha)::Float64
     elseif panel.aero_model == POLAR_MATRICES    
-        cd = panel.cd_interp(alpha, panel.beta)::Float64
-        cm = panel.cm_interp(alpha, panel.beta)::Float64
+        cd = panel.cd_interp(alpha, panel.delta)::Float64
+        cm = panel.cm_interp(alpha, panel.delta)::Float64
     elseif !(panel.aero_model == INVISCID)
         throw(ArgumentError("Unsupported aero model: $(panel.aero_model)"))
     end

src/plotting.jl

@@ -839,23 +839,23 @@ function VortexStepMethod.plot_polars(
 end
 
 """
-    plot_polar_data(body_aero::BodyAerodynamics; alphas=collect(deg2rad.(-5:0.3:25)), beta_tes=collect(deg2rad.(-5:0.3:25)))
+    plot_polar_data(body_aero::BodyAerodynamics; alphas=collect(deg2rad.(-5:0.3:25)), delta_tes=collect(deg2rad.(-5:0.3:25)))
 
-Plot polar data (Cl, Cd, Cm) as 3D surfaces against alpha and beta_te angles. Beta_te is the trailing edge deflection angle
+Plot polar data (Cl, Cd, Cm) as 3D surfaces against alpha and delta_te angles. delta_te is the trailing edge deflection angle
 relative to the 2d airfoil or panel chord line.
 
 # Arguments
 - `body_aero`: Wing aerodynamics struct
 
 # Keyword arguments
 - `alphas`: Range of angle of attack values in radians (default: -5° to 25° in 0.3° steps)
-- `beta_tes`: Range of trailing edge angles in radians (default: -5° to 25° in 0.3° steps)
+- `delta_tes`: Range of trailing edge angles in radians (default: -5° to 25° in 0.3° steps)
 - `is_show`: Whether to display plots (default: true)
 - `use_tex`: if the external `pdflatex` command shall be used
 """
 function VortexStepMethod.plot_polar_data(body_aero::BodyAerodynamics; 
         alphas=collect(deg2rad.(-5:0.3:25)), 
-        beta_tes = collect(deg2rad.(-5:0.3:25)),
+        delta_tes = collect(deg2rad.(-5:0.3:25)),
         is_show = true,
         use_tex = false
         )
@@ -877,10 +877,10 @@ function VortexStepMethod.plot_polar_data(body_aero::BodyAerodynamics;
             ax = fig.add_subplot(1, 3, idx, projection="3d")
 
             # Create interpolation matrix
-            interp_matrix = zeros(length(alphas), length(beta_tes))
-            interp_matrix .= [interp(alpha, beta_te) for alpha in alphas, beta_te in beta_tes]
-            X = collect(beta_tes) .+ zeros(length(alphas))'
-            Y = collect(alphas)' .+ zeros(length(beta_tes))
+            interp_matrix = zeros(length(alphas), length(delta_tes))
+            interp_matrix .= [interp(alpha, delta_te) for alpha in alphas, delta_te in delta_tes]
+            X = collect(delta_tes) .+ zeros(length(alphas))'
+            Y = collect(alphas)' .+ zeros(length(delta_tes))
 
             # Plot surface
             ax.plot_wireframe(X, Y, interp_matrix, 
@@ -891,10 +891,10 @@ function VortexStepMethod.plot_polar_data(body_aero::BodyAerodynamics;
                             alpha=0.6)
 
             # Set labels and title
-            ax.set_xlabel(L"$\beta$ [rad]")
+            ax.set_xlabel(L"$\delta$ [rad]")
             ax.set_ylabel(L"$\alpha$ [rad]")
             ax.set_zlabel(label)
-            ax.set_title(label * L" vs $\alpha$ and $\beta$")
+            ax.set_title(label * L" vs $\alpha$ and $\delta$")
             ax.grid(true)
         end
 

src/wing_geometry.jl

@@ -310,20 +310,20 @@
             return (alpha_left, CL_data, CD_data, CM_data)
 
         elseif model_type == POLAR_MATRICES
-            alpha_left, beta_left, CL_left, CD_left, CM_left = polar_left
-            alpha_right, beta_right, CL_right, CD_right, CM_right = polar_right
+            alpha_left, delta_left, CL_left, CD_left, CM_left = polar_left
+            alpha_right, delta_right, CL_right, CD_right, CM_right = polar_right
 
             # Create common alpha array
             !all(isapprox.(alpha_left, alpha_right)) && @error "Make sure you use the same alpha range for all your interpolations."
-            !all(isapprox.(beta_left, beta_right)) && @error "Make sure you use the same alpha range for all your interpolations."
-            !isa(CL_right, AbstractMatrix) && @error "Provide polar data in the correct format: (alpha, beta, cl, cd, cm)"
+            !all(isapprox.(delta_left, delta_right)) && @error "Make sure you use the same alpha range for all your interpolations."
+            !isa(CL_right, AbstractMatrix) && @error "Provide polar data in the correct format: (alpha, delta, cl, cd, cm)"
 
             # Weighted interpolation
             CL_data = CL_left .* left_weight .+ CL_right .* right_weight
             CD_data = CD_left .* left_weight .+ CD_right .* right_weight
             CM_data = CM_left .* left_weight .+ CM_right .* right_weight
 
-            return (alpha_left, beta_left, CL_data, CD_data, CM_data)
+            return (alpha_left, delta_left, CL_data, CD_data, CM_data)
         end
 
     elseif model_type === LEI_AIRFOIL_BREUKELS

test/test_body_aerodynamics.jl

@@ -262,12 +262,12 @@ end
         v_a = [cos(aoa), 0.0, sin(aoa)] .* v_a
 
         coord = if wing_type === :rectangular
-            twist = range(-0.5, 0.5, length=N)
+            theta = range(-0.5, 0.5, length=N)
             beta = range(-2, 2, length=N)
             generate_coordinates_rect_wing(
                 fill(max_chord, N),
                 span,
-                twist,
+                theta,
                 beta,
                 N,
                 "lin"

test/test_wing_geometry.jl

@@ -70,17 +70,17 @@ end
 
         # Create matrix data with NaNs
         alpha = collect(range(-10, 10, 21))
-        beta = collect(range(-5, 5, 11))
-        cl = [cos(a) * cos(b) for a in alpha, b in beta]
-        cd = [sin(a) * sin(b) for a in alpha, b in beta]
+        delta = collect(range(-5, 5, 11))
+        cl = [cos(a) * cos(b) for a in alpha, b in delta]
+        cd = [sin(a) * sin(b) for a in alpha, b in delta]
         cm = zeros(21, 11)
 
         # Insert NaNs at various positions
         cl[5,3] = NaN
         cd[10,5] = NaN
         cm[15,7] = NaN
 
-        aero_data = (alpha, beta, cl, cd, cm)
+        aero_data = (alpha, delta, cl, cd, cm)
         add_section!(wing, [0.0, 0.0, 0.0], [1.0, 0.0, 0.0], POLAR_MATRICES, aero_data)
 
         # Check if NaNs were removed consistently
@@ -89,7 +89,7 @@ end
         @test !any(isnan, cleaned_data[4])   # cd
         @test !any(isnan, cleaned_data[5])   # cm
         @test all(diff(cleaned_data[1]) .> 0) # alpha still monotonic
-        @test all(diff(cleaned_data[2]) .> 0) # beta still monotonic
+        @test all(diff(cleaned_data[2]) .> 0) # delta still monotonic
     end
 
     @testset "Robustness left to right" begin

test/utils.jl

@@ -20,15 +20,15 @@ Generate 3D coordinates of a rectangular wing with twist and dihedral.
 # Arguments
 - `chord::Vector{Float64}`: Chord lengths of wing panels
 - `span::Float64`: Total wing span
-- `twist::Vector{Float64}`: Twist angles in radians
+- `theta::Vector{Float64}`: Twist angles in radians
 - `beta::Vector{Float64}`: Dihedral angles in radians
 - `N::Int`: Number of spanwise panels
 - `dist::String`: Distribution type ("cos" or "lin")
 
 # Returns
 - `coord::Matrix{Float64}`: 2N×3 matrix of coordinates
 """
-function generate_coordinates_rect_wing(chord, span, twist, beta, N, dist)
+function generate_coordinates_rect_wing(chord, span, theta, beta, N, dist)
     coord = zeros(2 * N, 3)
     span_points = if dist == "cos"
         cosspace(-span/2, span/2, N)
@@ -40,14 +40,14 @@ function generate_coordinates_rect_wing(chord, span, twist, beta, N, dist)
 
     for i in 1:N
         coord[2i-1, :] = [
-            -0 * chord[i] * cos(twist[i]),
+            -0 * chord[i] * cos(theta[i]),
             span_points[i],
-            0 * chord[i] * sin(twist[i]) - abs(span_points[i] * sin(beta[i]))
+            0 * chord[i] * sin(theta[i]) - abs(span_points[i] * sin(beta[i]))
         ]
         coord[2i, :] = [
-            1 * chord[i] * cos(twist[i]),
+            1 * chord[i] * cos(theta[i]),
             span_points[i],
-            -1 * chord[i] * sin(twist[i]) - abs(span_points[i] * sin(beta[i]))
+            -1 * chord[i] * sin(theta[i]) - abs(span_points[i] * sin(beta[i]))
         ]
     end
     return coord