"""Estimation of rolling moment du to the ailerons."""
# 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 .figure_digitization import FigureDigitization
from ..constants import SUBMODEL_CN_AILERON
[docs]@oad.RegisterSubmodel(SUBMODEL_CN_AILERON, "fastga.submodel.aerodynamics.aileron.yaw_moment.legacy")
class ComputeCnDeltaAileron(FigureDigitization):
"""
Yaw moment due to aileron deflection (also called adverse aileron yaw). Depends on the wing
lift, hence on the angle of attack, so the same remark as in ..compute_cy_yaw_rate.py holds.
The convention from :cite:`roskampart6:1985` are used, meaning that for lateral derivative,
the reference length is the wing span.
Based on :cite:`roskampart6:1985` section 10.3.8.
"""
[docs] def initialize(self):
self.options.declare("low_speed_aero", default=False, types=bool)
[docs] def setup(self):
self.add_input("data:geometry:wing:aileron:span_ratio", val=np.nan)
self.add_input("data:geometry:wing:taper_ratio", val=np.nan)
self.add_input("data:geometry:wing:aspect_ratio", val=np.nan)
if self.options["low_speed_aero"]:
self.add_input(
"settings:aerodynamics:reference_flight_conditions:low_speed:AOA",
units="rad",
val=5.0 * np.pi / 180.0,
)
self.add_input(
"data:aerodynamics:aileron:low_speed:Cl_delta_a", val=np.nan, units="rad**-1"
)
self.add_input("data:aerodynamics:wing:low_speed:CL0_clean", val=np.nan)
self.add_input("data:aerodynamics:wing:low_speed:CL_alpha", val=np.nan, units="rad**-1")
self.add_output("data:aerodynamics:aileron:low_speed:Cn_delta_a", units="rad**-1")
else:
self.add_input(
"settings:aerodynamics:reference_flight_conditions:cruise:AOA",
units="rad",
val=1.0 * np.pi / 180.0,
)
self.add_input(
"data:aerodynamics:aileron:cruise:Cl_delta_a", val=np.nan, units="rad**-1"
)
self.add_input("data:aerodynamics:wing:cruise:CL0_clean", val=np.nan)
self.add_input("data:aerodynamics:wing:cruise:CL_alpha", val=np.nan, units="rad**-1")
self.add_output("data:aerodynamics:aileron:cruise:Cn_delta_a", units="rad**-1")
self.declare_partials("*", "*", method="fd")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
wing_taper_ratio = inputs["data:geometry:wing:taper_ratio"]
wing_aspect_ratio = inputs["data:geometry:wing:aspect_ratio"]
aileron_span_ratio = inputs["data:geometry:wing:aileron:span_ratio"]
if self.options["low_speed_aero"]:
aoa_ref = inputs["settings:aerodynamics:reference_flight_conditions:low_speed:AOA"]
cl_delta_a = inputs["data:aerodynamics:aileron:low_speed:Cl_delta_a"]
cl_0_wing = inputs["data:aerodynamics:wing:low_speed:CL0_clean"]
cl_alpha_wing = inputs["data:aerodynamics:wing:low_speed:CL_alpha"]
else:
aoa_ref = inputs["settings:aerodynamics:reference_flight_conditions:cruise:AOA"]
cl_delta_a = inputs["data:aerodynamics:aileron:cruise:Cl_delta_a"]
cl_0_wing = inputs["data:aerodynamics:wing:cruise:CL0_clean"]
cl_alpha_wing = inputs["data:aerodynamics:wing:cruise:CL_alpha"]
aileron_inner_span_ratio = 1.0 - aileron_span_ratio
cl_w = cl_0_wing + cl_alpha_wing * aoa_ref
correlation_constant = self.cn_delta_a_correlation_constant(
wing_taper_ratio, wing_aspect_ratio, aileron_inner_span_ratio
)
cn_delta_a = correlation_constant * cl_w * cl_delta_a
if self.options["low_speed_aero"]:
outputs["data:aerodynamics:aileron:low_speed:Cn_delta_a"] = cn_delta_a
else:
outputs["data:aerodynamics:aileron:cruise:Cn_delta_a"] = cn_delta_a