# This file is part of Marius Peter's airfoil analysis package (this program). # # This program is free software: you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by # the Free Software Foundation, either version 3 of the License, or # (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program. If not, see . import sys import os.path import numpy as np from math import sqrt import matplotlib.pyplot as plt class Airfoil: '''Performs structural evaluations for the airfoil passed as argument.''' def __init__(self, airfoil): self.airfoil = airfoil print(self.airfoil) # Global dimensions self.chord = airfoil.chord self.semi_span = airfoil.semi_span # mass and area self.mass_total = float(airfoil.mass + airfoil.spar.mass + airfoil.stringer.mass) self.mass_dist = [] # Upper coordinates self.x_u = airfoil.x_u self.z_u = airfoil.z_u # Lower coordinates self.x_l = airfoil.x_l self.z_l = airfoil.z_l # Spars self.spar = airfoil.spar # Stringers self.stringer = airfoil.stringer # Lifts self.lift_rectangular = [] self.lift_elliptical = [] self.lift = [] # Drag self.drag = [] def info_print(self, round): ''' Print all the component's evaluated data to the terminal. This function's output is piped to the 'save_data' function below. ''' name = ' CREATOR DATA ' num_of_dashes = len(name) print(num_of_dashes * '-') print(name) print('Evaluating:', self.airfoil) print('Chord length:', self.chord) print('Semi-span:', self.semi_span) print('Total airfoil mass:', self.mass_total) print('Centroid location:', np.around(self.centroid, round + 1)) print(num_of_dashes * '-') print('Rectangular lift:\n', np.around(self.lift_rectangular, round)) print('Elliptical lift:\n', np.around(self.lift_elliptical, round)) print('Combined lift:\n', np.around(self.lift, round)) print('Distribution of mass:\n', np.around(self.mass_dist, round)) print('Drag:\n', np.around(self.drag, round)) return None def info_save(self, save_dir_path, number): '''Save all the object's coordinates (must be full path).''' file_name = 'airfoil_{}_eval.txt'.format(number) full_path = os.path.join(save_dir_path, file_name) try: with open(full_path, 'w') as sys.stdout: self.info_print(6) # This line required to reset behavior of sys.stdout sys.stdout = sys.__stdout__ print('Successfully wrote to file {}'.format(full_path)) except IOError: print('Unable to write {} to specified directory.\n' .format(file_name), 'Was the full path passed to the function?') return None # All these functions take integer arguments and return lists. def get_lift_rectangular(self, lift): L_prime = [lift / (self.semi_span * 2) for x in range(self.semi_span)] return L_prime def get_lift_elliptical(self, L_0): L_prime = [L_0 * sqrt(1 - (y / self.semi_span) ** 2) for y in range(self.semi_span)] return L_prime def get_lift_total(self): F_z = [(self.lift_rectangular[_] + self.lift_elliptical[_]) / 2 for _ in range(len(self.lift_rectangular))] return F_z def get_mass_distribution(self, total_mass): F_z = [total_mass / self.semi_span for x in range(0, self.semi_span)] return F_z def get_drag(self, drag): # Transform semi-span integer into list semi_span = [x for x in range(0, self.semi_span)] # Drag increases after 80% of the semi_span cutoff = round(0.8 * self.semi_span) # Drag increases by 25% after 80% of the semi_span F_x = [drag for x in semi_span[0:cutoff]] F_x.extend([1.25 * drag for x in semi_span[cutoff:]]) return F_x def get_centroid(self): '''Return the coordinates of the centroid.''' area = self.airfoil.stringer.area x_stringers = self.airfoil.stringer.x_u + self.airfoil.stringer.x_l x_centroid = sum([x * area for x in x_stringers]) / \ (len(x_stringers) * area) z_stringers = self.airfoil.stringer.z_u + self.airfoil.stringer.z_l z_centroid = sum([x * area for x in z_stringers]) / \ (len(x_stringers) * area) return(x_centroid, z_centroid) def get_I_x(): pass def get_I_z(): pass def get_I_xz(): pass def analysis(self): '''Perform all analysis calculations and store in class instance.''' self.drag = self.get_drag(10) self.lift_rectangular = self.get_lift_rectangular(10) self.lift_elliptical = self.get_lift_elliptical(15) self.lift = self.get_lift_total() self.mass_dist = self.get_mass_distribution(self.mass_total) self.centroid = self.get_centroid() self.I_x = self.get_I_x() self.I_z = self.get_I_z() self.I_xz = self.get_I_xz() return None def plot(self): '''This function plots analysis results over the airfoil's geometry.''' # Plot chord x_chord = [0, self.chord] y_chord = [0, 0] plt.plot(x_chord, y_chord, linewidth='1') # Plot quarter chord q = self.chord / 4 plt.plot(q, 0, '.', color='g', markersize=24, label='quarter-chord') # Plot upper surface plt.plot(self.x_u, self.z_u, '', color='b', linewidth='1') # Plot lower surface plt.plot(self.x_l, self.z_l, '', color='b', linewidth='1') # Plot spars for _ in range(0, len(self.spar.x_u)): x = (self.spar.x_u[_], self.spar.x_l[_]) y = (self.spar.z_u[_], self.spar.z_l[_]) plt.plot(x, y, '.-', color='b') # Plot upper stringers for _ in range(0, len(self.stringer.x_u)): x = self.stringer.x_u[_] y = self.stringer.z_u[_] plt.plot(x, y, '.', color='y', markersize=12) # Plot lower stringers for _ in range(0, len(self.stringer.x_l)): x = self.stringer.x_l[_] y = self.stringer.z_l[_] plt.plot(x, y, '.', color='y', markersize=12) # Plot centroid x = self.centroid[0] y = self.centroid[1] plt.plot(x, y, '.', color='r', markersize=24, label='centroid') # Graph formatting plt.xlabel('X axis') plt.ylabel('Z axis') plot_bound = self.x_u[-1] plt.xlim(- 0.10 * plot_bound, 1.10 * plot_bound) plt.ylim(- (1.10 * plot_bound / 2), (1.10 * plot_bound / 2)) plt.gca().set_aspect('equal', adjustable='box') plt.grid(axis='both', linestyle=':', linewidth=1) plt.show() # plt.pause(1) # plt.close() return None