"""Estimation of total profile drag."""
# 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
import fastoad.api as oad
from openmdao.core.explicitcomponent import ExplicitComponent
from ..constants import SUBMODEL_CD0_SUM
[docs]@oad.RegisterSubmodel(SUBMODEL_CD0_SUM, "fastga.submodel.aerodynamics.sum.cd0.legacy")
class Cd0Total(ExplicitComponent):
"""
Profile drag estimation for the whole aircraft. It is the simple sum of all the profile drag
since every subpart was computed with the wing area as a reference and the interaction are
taken into account with interference factors
Based on : The drag build-up method in Gudmundsson, Snorri. General aviation aircraft design:
Applied Methods and Procedures. Butterworth-Heinemann, 2013.
"""
[docs] def initialize(self):
self.options.declare("low_speed_aero", default=False, types=bool)
[docs] def setup(self):
self.add_input(
"settings:aerodynamics:aircraft:undesirable_drag:k_factor",
val=1.25,
desc="Correction coefficient to take into account the other undesirable drag, "
"default is 1.25 as suggested in Gudmundsson",
)
if self.options["low_speed_aero"]:
self.add_input("data:aerodynamics:wing:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:fuselage:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:horizontal_tail:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:vertical_tail:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:nacelles:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:landing_gear:low_speed:CD0", val=np.nan)
self.add_input("data:aerodynamics:other:low_speed:CD0", val=np.nan)
self.add_output("data:aerodynamics:aircraft:low_speed:CD0")
self.declare_partials("*", "*", method="exact")
else:
self.add_input("data:aerodynamics:wing:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:fuselage:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:horizontal_tail:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:vertical_tail:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:nacelles:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:landing_gear:cruise:CD0", val=np.nan)
self.add_input("data:aerodynamics:other:cruise:CD0", val=np.nan)
self.add_output("data:aerodynamics:aircraft:cruise:CD0")
self.declare_partials("*", "*", method="exact")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
if self.options["low_speed_aero"]:
cd0_wing = inputs["data:aerodynamics:wing:low_speed:CD0"]
cd0_fus = inputs["data:aerodynamics:fuselage:low_speed:CD0"]
cd0_ht = inputs["data:aerodynamics:horizontal_tail:low_speed:CD0"]
cd0_vt = inputs["data:aerodynamics:vertical_tail:low_speed:CD0"]
cd0_nac = inputs["data:aerodynamics:nacelles:low_speed:CD0"]
cd0_lg = inputs["data:aerodynamics:landing_gear:low_speed:CD0"]
cd0_other = inputs["data:aerodynamics:other:low_speed:CD0"]
else:
cd0_wing = inputs["data:aerodynamics:wing:cruise:CD0"]
cd0_fus = inputs["data:aerodynamics:fuselage:cruise:CD0"]
cd0_ht = inputs["data:aerodynamics:horizontal_tail:cruise:CD0"]
cd0_vt = inputs["data:aerodynamics:vertical_tail:cruise:CD0"]
cd0_nac = inputs["data:aerodynamics:nacelles:cruise:CD0"]
cd0_lg = inputs["data:aerodynamics:landing_gear:cruise:CD0"]
cd0_other = inputs["data:aerodynamics:other:cruise:CD0"]
# CRUD (other undesirable drag). Factor from Gudmundsson book
crud_factor = inputs["settings:aerodynamics:aircraft:undesirable_drag:k_factor"]
cd0 = crud_factor * (cd0_wing + cd0_fus + cd0_ht + cd0_vt + cd0_lg + cd0_nac + cd0_other)
if self.options["low_speed_aero"]:
outputs["data:aerodynamics:aircraft:low_speed:CD0"] = cd0
else:
outputs["data:aerodynamics:aircraft:cruise:CD0"] = cd0
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
crud_factor = inputs["settings:aerodynamics:aircraft:undesirable_drag:k_factor"]
if self.options["low_speed_aero"]:
cd0_wing = inputs["data:aerodynamics:wing:low_speed:CD0"]
cd0_fus = inputs["data:aerodynamics:fuselage:low_speed:CD0"]
cd0_ht = inputs["data:aerodynamics:horizontal_tail:low_speed:CD0"]
cd0_vt = inputs["data:aerodynamics:vertical_tail:low_speed:CD0"]
cd0_nac = inputs["data:aerodynamics:nacelles:low_speed:CD0"]
cd0_lg = inputs["data:aerodynamics:landing_gear:low_speed:CD0"]
cd0_other = inputs["data:aerodynamics:other:low_speed:CD0"]
partials[
"data:aerodynamics:aircraft:low_speed:CD0", "data:aerodynamics:wing:low_speed:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"data:aerodynamics:fuselage:low_speed:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"data:aerodynamics:horizontal_tail:low_speed:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"data:aerodynamics:vertical_tail:low_speed:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"data:aerodynamics:nacelles:low_speed:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"data:aerodynamics:landing_gear:low_speed:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0", "data:aerodynamics:other:low_speed:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:low_speed:CD0",
"settings:aerodynamics:aircraft:undesirable_drag:k_factor",
] = cd0_wing + cd0_fus + cd0_ht + cd0_vt + cd0_lg + cd0_nac + cd0_other
else:
cd0_wing = inputs["data:aerodynamics:wing:cruise:CD0"]
cd0_fus = inputs["data:aerodynamics:fuselage:cruise:CD0"]
cd0_ht = inputs["data:aerodynamics:horizontal_tail:cruise:CD0"]
cd0_vt = inputs["data:aerodynamics:vertical_tail:cruise:CD0"]
cd0_nac = inputs["data:aerodynamics:nacelles:cruise:CD0"]
cd0_lg = inputs["data:aerodynamics:landing_gear:cruise:CD0"]
cd0_other = inputs["data:aerodynamics:other:cruise:CD0"]
partials[
"data:aerodynamics:aircraft:cruise:CD0", "data:aerodynamics:wing:cruise:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0", "data:aerodynamics:fuselage:cruise:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0",
"data:aerodynamics:horizontal_tail:cruise:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0",
"data:aerodynamics:vertical_tail:cruise:CD0",
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0", "data:aerodynamics:nacelles:cruise:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0", "data:aerodynamics:landing_gear:cruise:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0", "data:aerodynamics:other:cruise:CD0"
] = crud_factor
partials[
"data:aerodynamics:aircraft:cruise:CD0",
"settings:aerodynamics:aircraft:undesirable_drag:k_factor",
] = cd0_wing + cd0_fus + cd0_ht + cd0_vt + cd0_lg + cd0_nac + cd0_other