# 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 openmdao.api as om
import fastoad.api as oad
from fastga.models.aerodynamics.constants import SUBMODEL_CL_Q_HT
[docs]@oad.RegisterSubmodel(
SUBMODEL_CL_Q_HT, "fastga.submodel.aerodynamics.horizontal_tail.cl_pitch_velocity.legacy"
)
class ComputeCLPitchVelocityHorizontalTail(om.ExplicitComponent):
"""
Computation of the contribution of the horizontal tail to the increase in lift due to a pitch
velocity. The convention from :cite:`roskampart6:1985` are used, meaning that,
for the derivative with respect to yaw and roll, the rotation speed are made dimensionless by
multiplying them by the wing span and dividing them by 2 times the airspeed.
Based on :cite:`roskampart6:1985` section 10.2.7
"""
[docs] def initialize(self):
self.options.declare("low_speed_aero", default=False, types=bool)
[docs] def setup(self):
self.add_input("data:geometry:wing:area", units="m**2", val=np.nan)
self.add_input("data:geometry:horizontal_tail:area", units="m**2", val=np.nan)
self.add_input("data:geometry:horizontal_tail:volume_coefficient", val=np.nan)
self.add_input("data:aerodynamics:horizontal_tail:efficiency", val=np.nan)
ls_tag = "low_speed" if self.options["low_speed_aero"] else "cruise"
self.add_input(
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_alpha", val=np.nan, units="rad**-1"
)
self.add_output("data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q", units="rad**-1")
self.declare_partials(
of="data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
wrt=[
"data:geometry:wing:area",
"data:geometry:horizontal_tail:area",
"data:geometry:horizontal_tail:volume_coefficient",
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_alpha",
"data:aerodynamics:horizontal_tail:efficiency",
],
method="exact",
)
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
eta_h = inputs["data:aerodynamics:horizontal_tail:efficiency"]
volume_coeff_ht = inputs["data:geometry:horizontal_tail:volume_coefficient"]
# From the instructions section 10.2.7, it seems to suggest that we need the lift curve
# coefficient with respect to the area of the horizontal tail hence the change in
# reference surface.
wing_area = inputs["data:geometry:wing:area"]
ht_area = inputs["data:geometry:horizontal_tail:area"]
ls_tag = "low_speed" if self.options["low_speed_aero"] else "cruise"
cl_alpha_ht = inputs["data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_alpha"]
outputs["data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q"] = (
2.0 * cl_alpha_ht * eta_h * volume_coeff_ht * wing_area / ht_area
)
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
eta_h = inputs["data:aerodynamics:horizontal_tail:efficiency"]
volume_coeff_ht = inputs["data:geometry:horizontal_tail:volume_coefficient"]
wing_area = inputs["data:geometry:wing:area"]
ht_area = inputs["data:geometry:horizontal_tail:area"]
ls_tag = "low_speed" if self.options["low_speed_aero"] else "cruise"
cl_alpha_ht = inputs["data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_alpha"]
partials[
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
"data:aerodynamics:horizontal_tail:efficiency",
] = 2.0 * cl_alpha_ht * volume_coeff_ht * wing_area / ht_area
partials[
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
"data:geometry:horizontal_tail:volume_coefficient",
] = 2.0 * cl_alpha_ht * eta_h * wing_area / ht_area
partials[
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_alpha",
] = 2.0 * volume_coeff_ht * eta_h * wing_area / ht_area
partials[
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
"data:geometry:wing:area",
] = 2.0 * volume_coeff_ht * eta_h * cl_alpha_ht / ht_area
partials[
"data:aerodynamics:horizontal_tail:" + ls_tag + ":CL_q",
"data:geometry:horizontal_tail:area",
] = -2.0 * volume_coeff_ht * eta_h * cl_alpha_ht * wing_area / ht_area**2.0