"""
Computation of the non-equilibrated aircraft polars
"""
# This file is part of FAST-OAD_CS23 : A framework for rapid Overall Aircraft Design
# Copyright (C) 2022 ONERA & ISAE-SUPAERO
# FAST 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 <https://www.gnu.org/licenses/>.
import numpy as np
from openmdao.core.explicitcomponent import ExplicitComponent
from fastga.models.aerodynamics.constants import POLAR_POINT_COUNT
[docs]class ComputeNonEquilibratedPolar(ExplicitComponent):
[docs] def initialize(self):
self.options.declare("low_speed_aero", default=False, types=bool)
[docs] def setup(self):
if self.options["low_speed_aero"]:
self.add_input("data:aerodynamics:wing:low_speed:CL0_clean", val=np.nan)
self.add_input("data:aerodynamics:wing:low_speed:induced_drag_coefficient", val=np.nan)
self.add_input("data:aerodynamics:aircraft:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:wing:low_speed:CL_alpha", val=np.nan, units="rad**-1")
self.add_output(
"data:aerodynamics:aircraft:low_speed:CD",
shape=POLAR_POINT_COUNT,
)
self.add_output(
"data:aerodynamics:aircraft:low_speed:CL",
shape=POLAR_POINT_COUNT,
)
else:
self.add_input("data:aerodynamics:wing:cruise:CL0_clean", val=np.nan)
self.add_input("data:aerodynamics:wing:cruise:induced_drag_coefficient", val=np.nan)
self.add_input("data:aerodynamics:aircraft:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:wing:cruise:CL_alpha", val=np.nan, units="rad**-1")
self.add_output("data:aerodynamics:aircraft:cruise:CD", shape=POLAR_POINT_COUNT)
self.add_output("data:aerodynamics:aircraft:cruise:CL", shape=POLAR_POINT_COUNT)
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
if self.options["low_speed_aero"]:
coeff_k = inputs["data:aerodynamics:wing:low_speed:induced_drag_coefficient"]
cd0 = inputs["data:aerodynamics:aircraft:low_speed:CD0"]
cl0 = inputs["data:aerodynamics:wing:low_speed:CL0_clean"]
cl_alpha = inputs["data:aerodynamics:wing:low_speed:CL_alpha"]
else:
coeff_k = inputs["data:aerodynamics:wing:cruise:induced_drag_coefficient"]
cd0 = inputs["data:aerodynamics:aircraft:cruise:CD0"]
cl0 = inputs["data:aerodynamics:wing:cruise:CL0_clean"]
cl_alpha = inputs["data:aerodynamics:wing:cruise:CL_alpha"]
alpha_array = np.linspace(0, 15, POLAR_POINT_COUNT) * np.pi / 180
cl_array = cl0 + alpha_array * cl_alpha
cd_array = cd0 + coeff_k * cl_array**2
if self.options["low_speed_aero"]:
outputs["data:aerodynamics:aircraft:low_speed:CD"] = cd_array
outputs["data:aerodynamics:aircraft:low_speed:CL"] = cl_array
else:
outputs["data:aerodynamics:aircraft:cruise:CD"] = cd_array
outputs["data:aerodynamics:aircraft:cruise:CL"] = cl_array