def mean_sweep_angle(self, x_nondim=0.25) -> float:
"""
Returns the mean sweep angle (in degrees) of the wing, relative to the x-axis.
Positive sweep is backwards, negative sweep is forward.
By changing `x_nondim`, you can change whether it's leading-edge sweep (0), quarter-chord sweep (0.25),
trailing-edge sweep (1), or anything else.
:return: The mean sweep angle, in degrees.
"""
root_quarter_chord = self._compute_xyz_of_WingXSec(0,
x_nondim=x_nondim,
y_nondim=0)
tip_quarter_chord = self._compute_xyz_of_WingXSec(-1,
x_nondim=x_nondim,
y_nondim=0)
vec = tip_quarter_chord - root_quarter_chord
vec_norm = vec / np.linalg.norm(vec)
sin_sweep = vec_norm[0] # from dot product with x_hat
sweep_deg = np.arcsind(sin_sweep)
return sweep_deg
def mean_sweep_angle(self) -> float:
"""
Returns the mean quarter-chord sweep angle (in degrees) of the wing, relative to the x-axis.
Positive sweep is backwards, negative sweep is forward.
:return:
"""
root_quarter_chord = self._compute_xyz_of_WingXSec(
0,
x_nondim=0.25,
y_nondim=0
)
tip_quarter_chord = self._compute_xyz_of_WingXSec(
-1,
x_nondim=0.25,
y_nondim=0
)
vec = tip_quarter_chord - root_quarter_chord
vec_norm = vec / np.linalg.norm(vec)
sin_sweep = vec_norm[0] # from dot product with x_hat
sweep_deg = np.arcsind(sin_sweep)
return sweep_deg
def mean_sweep_angle(self) -> float:
"""
Returns the mean quarter-chord sweep angle (in degrees) of the wing, relative to the x-axis.
Positive sweep is backwards, negative sweep is forward.
:return:
"""
root_quarter_chord = self.xsecs[0].quarter_chord()
tip_quarter_chord = self.xsecs[-1].quarter_chord()
vec = tip_quarter_chord - root_quarter_chord
vec_norm = vec / np.linalg.norm(vec)
sin_sweep = vec_norm[0] # from dot product with x_hat
sweep_deg = np.arcsind(sin_sweep)
return sweep_deg
def solar_elevation_angle(latitude, day_of_year, time):
"""
Elevation angle of the sun [degrees] for a local observer.
:param latitude: Latitude [degrees]
:param day_of_year: Julian day (1 == Jan. 1, 365 == Dec. 31)
:param time: Time after local solar noon [seconds]
:return: Solar elevation angle [degrees] (angle between horizon and sun). Returns 0 if the sun is below the horizon.
"""
# Solar elevation angle (including seasonality, latitude, and time of day)
# Source: https://www.pveducation.org/pvcdrom/properties-of-sunlight/elevation-angle
declination = declination_angle(day_of_year)
solar_elevation_angle = np.arcsind(
np.sind(declination) * np.sind(latitude) +
np.cosd(declination) * np.cosd(latitude) * np.cosd(time / 86400 * 360)
) # in degrees
solar_elevation_angle = np.fmax(solar_elevation_angle, 0)
return solar_elevation_angle