# 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_CY_BETA_FUSELAGE
[docs]@oad.RegisterSubmodel(
SUBMODEL_CY_BETA_FUSELAGE, "fastga.submodel.aerodynamics.fuselage.side_force_beta.legacy"
)
class ComputeCyBetaFuselage(om.ExplicitComponent):
"""
Class to compute the contribution of the fuselage to the side force coefficient due to sideslip.
Based on :cite:`roskampart6:1985` section 10.2.4.1
"""
[docs] def setup(self):
self.add_input("data:geometry:fuselage:maximum_width", val=np.nan, units="m")
self.add_input("data:geometry:fuselage:maximum_height", val=np.nan, units="m")
self.add_input("data:geometry:wing:area", val=np.nan, units="m**2")
self.add_input("data:geometry:wing:root:z", val=np.nan, units="m")
self.add_output("data:aerodynamics:fuselage:Cy_beta", units="rad**-1")
self.declare_partials(of="*", wrt="*", method="exact")
[docs] def compute(self, inputs, outputs, discrete_inputs=None, discrete_outputs=None):
b_f = inputs["data:geometry:fuselage:maximum_width"]
h_f = inputs["data:geometry:fuselage:maximum_height"]
ave_fuse_diameter = np.sqrt(b_f * h_f)
wing_area = inputs["data:geometry:wing:area"]
z2_wing = inputs["data:geometry:wing:root:z"]
z2_ratio = 2.0 * z2_wing / ave_fuse_diameter
if z2_ratio >= 0:
k_i = 1 + 0.49 * z2_ratio
else:
k_i = 1 - 0.85 * z2_ratio
# Station x0 is assumed to be in the cylindrical part of the fuselage
s_0_fus = np.pi * (ave_fuse_diameter / 2) ** 2
cy_beta_fus = -2.0 * k_i * s_0_fus / wing_area
outputs["data:aerodynamics:fuselage:Cy_beta"] = cy_beta_fus
[docs] def compute_partials(self, inputs, partials, discrete_inputs=None):
b_f = inputs["data:geometry:fuselage:maximum_width"]
h_f = inputs["data:geometry:fuselage:maximum_height"]
wing_area = inputs["data:geometry:wing:area"]
z2_wing = inputs["data:geometry:wing:root:z"]
if z2_wing >= 0:
partials[
"data:aerodynamics:fuselage:Cy_beta", "data:geometry:fuselage:maximum_width"
] = -np.pi / (2.0 * wing_area) * (h_f + 0.49 * z2_wing / np.sqrt(b_f / h_f))
partials[
"data:aerodynamics:fuselage:Cy_beta", "data:geometry:fuselage:maximum_height"
] = -np.pi / (2.0 * wing_area) * (b_f + 0.49 * z2_wing / np.sqrt(h_f / b_f))
partials["data:aerodynamics:fuselage:Cy_beta", "data:geometry:wing:root:z"] = (
-0.49 * np.pi * np.sqrt(h_f * b_f) / wing_area
)
partials["data:aerodynamics:fuselage:Cy_beta", "data:geometry:wing:area"] = (
np.pi
/ (2.0 * wing_area**2.0)
* (h_f * b_f + 2.0 * 0.49 * z2_wing * np.sqrt(h_f * b_f))
)
else:
partials[
"data:aerodynamics:fuselage:Cy_beta", "data:geometry:fuselage:maximum_width"
] = -np.pi / (2.0 * wing_area) * (h_f - 0.85 * z2_wing / np.sqrt(b_f / h_f))
partials[
"data:aerodynamics:fuselage:Cy_beta", "data:geometry:fuselage:maximum_height"
] = -np.pi / (2.0 * wing_area) * (b_f + -0.85 * z2_wing / np.sqrt(h_f / b_f))
partials["data:aerodynamics:fuselage:Cy_beta", "data:geometry:wing:root:z"] = (
+0.85 * np.pi * np.sqrt(h_f * b_f) / wing_area
)
partials["data:aerodynamics:fuselage:Cy_beta", "data:geometry:wing:area"] = (
np.pi
/ (2.0 * wing_area**2.0)
* (h_f * b_f - 2.0 * 0.85 * z2_wing * np.sqrt(h_f * b_f))
)