Get the correct AoA from VSM

Project.toml

@@ -88,7 +88,7 @@ Sundials = "4.24"
 SymbolicIndexingInterface = "0"
 Timers = "0.1.5"
 UnPack = "1.0.2"
-VortexStepMethod = "1.2.2"
+VortexStepMethod = "1.2.3"
 WinchModels = "0.3.6"
 julia = "1.10, 1.11"
 

examples/ram_air_kite.jl

@@ -96,10 +96,7 @@ try
         sys_state.var_13 = s.integrator[sys.pulley_l0[1]]
         sys_state.var_14 = s.integrator[sys.pulley_l0[2]]
 
-        # Calculate apparent wind angle
-        va_kite_b = s.integrator[sys.va_kite_b]
-        e_x = s.integrator[sys.e_x]
-        sys_state.var_15 = rad2deg(acos(dot(normalize(va_kite_b), e_x)))
+        sys_state.var_15 = rad2deg(calc_aoa(s))
 
         log!(logger, sys_state)
     end

src/KiteModels.jl

@@ -61,7 +61,7 @@ export KPS3, KPS4, RamAirKite, KVec3, SimFloat, Measurement, PointMassSystem, Pr
 export calc_set_cl_cd!, copy_examples, copy_bin, update_sys_state!                            # helper functions
 export clear!, find_steady_state!, residual!                                                  # low level workers
 export init_sim!, init!, reinit!, next_step!, init_pos_vel, init_pos, model!                                 # high level workers
-export pos_kite, calc_height, calc_elevation, calc_azimuth, calc_heading, calc_course, calc_orient_quat  # getters
+export pos_kite, calc_height, calc_elevation, calc_azimuth, calc_heading, calc_course, calc_orient_quat, calc_aoa  # getters
 export calc_azimuth_north, calc_azimuth_east
 export winch_force, lift_drag, cl_cd, lift_over_drag, unstretched_length, tether_length, v_wind_kite     # getters
 export calculate_rotational_inertia!

src/ram_air_kite.jl

@@ -541,3 +541,15 @@ function get_prob_name(set::Settings)
     end
 end
 
+"""
+Calculate and return the angle of attack in rad
+"""
+function calc_aoa(s::RamAirKite)
+    alpha_array = s.vsm_solver.sol.alpha_array
+    middle = length(alpha_array) ÷ 2
+    if iseven(length(alpha_array))
+        return 0.5alpha_array[middle] + 0.5alpha_array[middle+1]
+    else
+        return alpha_array[middle+1]
+    end
+end