def test__rel_tang_angle(self):
airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/naca0018_360'
blade = vb.VawtBlade(0.2, airfoil_dir, 1)
# VECTORS rel_wind, blade_tangent_vector
test_values = [
[vec.Vector2(r=1, theta=1), vec.Vector2(r=1, theta=1.2), -0.2],
[vec.Vector2(r=1, theta=1), vec.Vector2(r=1, theta=1.2), -0.2]
]
for rel_wind, blade_tangent, rel_tang_angle in test_values:
self.assertAlmostEqual(blade._rel_tang_angle(rel_wind, blade_tangent), rel_tang_angle, 5, 'Wrong _rel_tang_angle')
def test_relative_wind(self):
test_values = pd.DataFrame(
{
'wind_vector': [
vec.Vector2(r=1, theta=1),
vec.Vector2(r=2, theta=2),
vec.Vector2(r=3, theta=0.5),
vec.Vector2(r=4, theta=-1)
],
'blade_tangent_vector': [
vec.Vector2(r=1, theta=-2),
vec.Vector2(r=1, theta=-1),
vec.Vector2(r=1, theta=0.1),
vec.Vector2(r=1, theta=3)
],
'rel_wind_r': [
0.14, 1.02, 3.94, 3.43
],
'rel_wind_theta': [
-0.5, 1.86, 0.4, -1.22
]
}
)
for index, test_case in test_values.iterrows():
answer = relative_wind(test_case['wind_vector'], test_case['blade_tangent_vector'])
self.assertAlmostEqual(answer.r, test_case['rel_wind_r'], 2, 'Wrong relative wind')
self.assertAlmostEqual(answer.theta, test_case['rel_wind_theta'], 2, 'Wrong relative wind')
def test_get_wind_vector(self):
test_values = [
[-1, 0.5, vec.Vector2(r=0.5, theta=2.14159265359)],
[1, 2.5, vec.Vector2(r=2.5, theta=-2.14159265359)],
[2, 3.5, vec.Vector2(r=3.5, theta=-1.14159265359)],
[3, 4.5, vec.Vector2(r=4.5, theta=-0.14159265359)],
[-2, 2, vec.Vector2(r=2, theta=1.14159265359)]
]
for tc in test_values:
wind_direction = tc[0]
wind_speed = tc[1]
answer = get_wind_vector(wind_direction, wind_speed)
self.assertAlmostEqual(answer.theta, tc[2].theta, 5, 'Wrong get_wind_vector theta')
self.assertAlmostEqual(answer.r, tc[2].r, 5, 'Wrong get_wind_vector radius')
def test_blade_chord_vec(self):
# calculate blade chord angle on blade_tangent_angle and pitch
airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/cp10_360'
blade = vb.VawtBlade(0.2, airfoil_dir, 1)
test_values = [
# pitch positive - rotates clockwise
# positive pitch - 'takes wind under the wing of ascending plane'
# positive pitch must be substracted from blade tangent to give actual blade chord vector
# blade_tangent_vector, pitch, blade_chord_vector.theta
[vec.Vector2(r=1, theta=-2), 1, -1],
[vec.Vector2(r=1, theta=-1), -0.5, -1.5],
[vec.Vector2(r=1, theta=0.1), 1, 1.1],
[vec.Vector2(r=1, theta=3), -1, 2]
]
for tc in test_values:
answer = blade._blade_chord_vec(tc[0], tc[1])
self.assertAlmostEqual(answer.theta, tc[2], 5, 'Wrong blade chord vector')
def test_angle_of_attack(self):
airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/cp10_360'
blade = vb.VawtBlade(0.2, airfoil_dir, 1)
test_values = [
# rel_wind_vector, blade_chord_vector, aoa_rad, aoa_360
[vec.Vector2(r=1, theta=-2.356194490192345), vec.Vector2(r=1, theta=-1.5707963267948966), -0.785398163397, -45],
[vec.Vector2(r=1, theta=-1), vec.Vector2(r=1, theta=-0.0007162025873375634), -0.9992837974126625, -57.25474412755153],
[vec.Vector2(r=1, theta=0.1), vec.Vector2(r=1, theta=-2), 2.1, 120.3211369],
[vec.Vector2(r=1, theta=3), vec.Vector2(r=1, theta=-2), -1.28318530, -73.5211024]
]
for tc in test_values:
aoa_rad, aoa_360 = blade._angle_of_attack(tc[0], tc[1])
self.assertAlmostEqual(aoa_rad, tc[2], 5, 'Wrong aoa_rad')
self.assertAlmostEqual(aoa_360, tc[3], 5, 'Wrong aoa_360')
def get_visualization_vectors(self, wind_vector, rotor_speed, theta,
pitch):
vectors = []
# relative wind vector
blade_speed = rotor_speed * self.rotor_radius
blade_tangent_line_angle = self._blade_tangent_line_angle(theta)
blade_tangent_vector = vec.Vector2(r=blade_speed,
theta=blade_tangent_line_angle)
vectors.append(('blade_tangent', blade_tangent_vector))
rel_wind = relative_wind(wind_vector, blade_tangent_vector)
vectors.append(('relative_wind', relative_wind))
re_number = reynolds_number(rel_wind.r, self.chord_length,
kinematic_viscosity)
blade_chord_vector = self._blade_chord_vec(blade_tangent_vector, pitch)
vectors.append(('blade_chord', blade_chord_vector))
aoa_rad, aoa_360 = self._angle_of_attack(rel_wind, blade_chord_vector)
cl, cd = self.get_coeffs(aoa_360, re_number)
fl = lift_force(air_density, rel_wind.r, self.chord_length, cl)
# lift force vector is perpendicular to rel_wind vector
fl_vec = vec.Vector2(r=fl, theta=rel_wind.rotated(math.pi / 2).theta)
vectors.append(('fl_vec', fl_vec))
fd = drag_force(air_density, rel_wind.r, self.chord_length, cd)
# drag force is opposite to rel_wind
fd_vec = vec.Vector2(r=fd, theta=rel_wind.rotated(math.pi).theta)
vectors.append(('fd_vec', fd_vec))
tf = tangential_force(fl, fd, aoa_rad)
# tangential force vector is opposite to blade tangential speed vector
tangential_force_vec = vec.Vector2(r=tf,
theta=blade_tangent_vector.rotated(
math.pi).theta)
vectors.append(('tangential_force_vec', tangential_force_vec))
return vectors
def get_tangential_force(self, wind_vector, rotor_speed, theta, pitch):
""""Calculate tangential force. Chord length is used instead of area.
Parameters
----------
wind_vector : vec
vector describes wind speed and direction
rotor_speed : float
rotor angular speed in rad/s
theta : float
position of blade relative to rotor 0 position in rad
pitch : float
angle between blade chord line and tangent line in rad
Returns
-------
ft : float
tangential force
"""
# relative wind vector
try:
blade_speed = rotor_speed * self.rotor_radius
except TypeError:
pass
blade_tangent_line_angle = self._blade_tangent_line_angle(theta)
blade_tangent_vector = vec.Vector2(r=blade_speed,
theta=blade_tangent_line_angle)
rel_wind = relative_wind(wind_vector, blade_tangent_vector)
re_number = reynolds_number(rel_wind.r, self.chord_length,
kinematic_viscosity)
blade_chord_vector = self._blade_chord_vec(blade_tangent_vector, pitch)
aoa_rad, aoa_360 = self._angle_of_attack(rel_wind, blade_chord_vector)
cl, cd = self.get_coeffs(aoa_360, re_number)
fl = lift_force(air_density, rel_wind.r, self.chord_length, cl)
fd = drag_force(air_density, rel_wind.r, self.chord_length, cd)
# casting angle is between rel_wind and blade tangent
casting_angle = self._rel_tang_angle(rel_wind, blade_tangent_vector)
return tangential_force(fl, fd, casting_angle)
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import vec
import learn.airfoil_dynamics.ct_plot.vawt_blade as vb
import math
wind_vector = vec.Vector2(r=3, theta=0)
# rotor_speed = 0.0001
rotor_speed = 0.0001
cp10_airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/cp10_360'
naca0018_airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/naca0018_360'
cp10_blade = vb.VawtBlade(0.2, cp10_airfoil_dir, 1)
naca0018_blade = vb.VawtBlade(0.2, naca0018_airfoil_dir, 1)
theta_range = [x * math.tau / 360 for x in range(-180, 180, 10)]
# theta_range = [vec.normalize_angle(theta) for theta in theta_range]
pitch_range = [x * math.tau / 360 for x in range(-90, 90, 10)]
# pitch_range = [x*math.tau/360 for x in range(-30, 30, 1)]
# theta_range = [x for x in range(0, 10, 1)]
# pitch_range = [x for x in range(-8, 7, 1)]
thetas = []
for theta in theta_range:
theta_ct_polar = [
cp10_blade.get_tangential_force(wind_vector, rotor_speed, theta, pitch)
for pitch in pitch_range
]
thetas.append(theta_ct_polar)
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import vec
import learn.airfoil_dynamics.ct_plot.vawt_blade as vb
import math
# plots tangential force in function of aoa and rotora blade theta
wind_vector = vec.Vector2(r=3, theta=2)
# rotor_speed = 0.0001
rotor_speed = 0.0001
# airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/cp10_360'
airfoil_dir = '/home/aa/vawt_env/learn/AeroDyn polars/naca0018_360'
blade = vb.VawtBlade(0.2, airfoil_dir, 1)
reynolds_range = [x * 10000 for x in range(10, 100, 10)]
# theta_range = [vec.normalize_angle(theta) for theta in theta_range]
aoa_range = [x for x in range(-180, 179, 10)]
cl_list = []
cd_list = []
for re_num in reynolds_range:
cl_polar = [blade.get_coeffs(aoa_360, re_num)[0] for aoa_360 in aoa_range]
cd_polar = [blade.get_coeffs(aoa_360, re_num)[1] for aoa_360 in aoa_range]
cl_list.append(cl_polar)
cd_list.append(cd_polar)
df_cl = pd.DataFrame(cl_list, index=reynolds_range, columns=aoa_range)
df_cd = pd.DataFrame(cd_list, index=reynolds_range, columns=aoa_range)
def rotate(vector2d, angle_radians):
x, y = vector2d.x, vector2d.y
xx = x * math.cos(angle_radians) - y * math.sin(angle_radians)
yy = x * math.sin(angle_radians) + y * math.cos(angle_radians)
return vec.Vector2(xx, yy)
def translate(vector2d, displacement_x, displacement_y):
displacement_vector = vec.Vector2(displacement_x, displacement_y)
return vector2d + displacement_vector