Source code for RCAIDE.Library.Methods.Performance.aircraft_aerodynamic_analysis
# RCAIDE/Methods/Performance/aircraft_aerodynamic_analysis.py
#
#
# Created: Dec 2024, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE imports
import RCAIDE
from RCAIDE.Framework.Core import Data
from RCAIDE.Library.Mission.Common.Pre_Process import geometry_preprocess_routine
# Pacakge imports
import numpy as np
import os, sys
#------------------------------------------------------------------------------
# aircraft_aerodynamic_analysis
#------------------------------------------------------------------------------
[docs]
def aircraft_aerodynamic_analysis(analyses = None,
angle_of_attacks = None,
mach_numbers = None,
non_dimensional_reynolds_numbers = None,
temperatures = None,
overwrite_reference = True,
altitude = None ):
"""
Computes aerodynamic coefficients across ranges of angle of attack and Mach numbers using vortex lattice methods.
Parameters
--------
vehicle : Vehicle
The vehicle instance to be analyzed
angle_of_attacks : ndarray
Array of angle of attack values to evaluate [radians]
mach_numbers : ndarray
Array of Mach numbers to evaluate
altitude : float, optional
Altitude for atmospheric properties [m], default 0
Returns
--------
results : Data
Container of analysis results including:
* Mach : ndarray
Evaluated Mach numbers
* alpha : ndarray
Evaluated angles of attack [rad]
* lift_coefficient : ndarray
Computed lift coefficients
* drag_coefficient : ndarray
Computed drag coefficients
* moment_coefficient : ndarray
Computed Y-moment coefficients
Notes
-----
The function uses the US Standard Atmosphere 1976 model for atmospheric properties
and evaluates aerodynamic coefficients using vortex lattice methods. Can use a surrogate model
for faster evaluation or just direct evaluation of the aerodynamics.
**Major Assumptions**
* Flow is steady and inviscid
* Small angle approximations apply
* Linear aerodynamics
* Atmospheric properties follow US Standard Atmosphere 1976
See Also
--------
RCAIDE.Library.Methods.Aerodynamics.Vortex_Lattice_Method
RCAIDE.Library.Attributes.Atmospheres.Earth.US_Standard_1976
"""
if type(analyses) != RCAIDE.Framework.Analyses.Vehicle:
raise AttributeError('RCAIDE analyses must be defined')
#------------------------------------------------------------------------
# Preprocess Geometry
#------------------------------------------------------------------------
geometry_preprocess_routine(analyses)
#------------------------------------------------------------------------
# Check size of arrays
#------------------------------------------------------------------------
if angle_of_attacks is None:
raise ValueError("Angle of attack range must be defined as nx1 2d-array")
if mach_numbers is None:
raise ValueError("Mach number range must be defined as nx1 2d-array ")
dim_AoA = len(angle_of_attacks[:, 0] )
dim_Mach = len(mach_numbers[:, 0] )
if dim_Mach != dim_AoA:
raise ValueError("Angle of attack and Mach number range must same dimension")
#------------------------------------------------------------------------
# setup flight conditions
#------------------------------------------------------------------------
# if altitude is specified
if altitude is not None:
atmosphere = RCAIDE.Framework.Analyses.Atmospheric.US_Standard_1976()
atmo_data = atmosphere.compute_values(altitude)
P = atmo_data.pressure
T = atmo_data.temperature
rho = atmo_data.density
a = atmo_data.speed_of_sound
mu = atmo_data.dynamic_viscosity
V = mach_numbers * a
non_dimensional_reynolds_numbers = V * rho / mu
# if non_dimensional_reynolds_numbers and temperatures are specified
elif non_dimensional_reynolds_numbers is not None and temperatures is not None:
dim_Re = len(non_dimensional_reynolds_numbers[:, 0] )
dim_T = len(temperatures[:, 0] )
if dim_Re != dim_T:
raise ValueError("Reynolds number and temperature range must same dimension")
elif dim_AoA != dim_T:
raise ValueError("Angle of attack and temperature range must same dimension")
atmosphere = RCAIDE.Framework.Analyses.Atmospheric.US_Standard_1976()
atmo_data = atmosphere.compute_values(0)
P = atmo_data.pressure
T = temperatures
a = RCAIDE.Library.Attributes.Gases.Air().compute_speed_of_sound(T=T)
V = mach_numbers * a
mu = RCAIDE.Library.Attributes.Gases.Air().compute_absolute_viscosity(T=T)
rho = non_dimensional_reynolds_numbers * mu / V
else:
raise ValueError("Specify either 1) altitude or combination or 2) non dimensional reynolds numbers and temperature arrays")
# -----------------------------------------------------------------
# Evaluate Without Surrogate
# -----------------------------------------------------------------
ctrl_pts = len(angle_of_attacks[:, 0] )
state = RCAIDE.Framework.Mission.Common.State()
state.conditions = RCAIDE.Framework.Mission.Common.Results()
state.conditions.freestream.density = rho * np.ones_like(angle_of_attacks)
state.conditions.freestream.dynamic_viscosity = mu * np.ones_like(angle_of_attacks)
state.conditions.freestream.temperature = T * np.ones_like(angle_of_attacks)
state.conditions.freestream.pressure = P * np.ones_like(angle_of_attacks)
state.conditions.freestream.dynamic_pressure = 0.5 * rho * V**2
state.conditions.aerodynamics.angles.alpha = angle_of_attacks
state.conditions.aerodynamics.angles.beta = angle_of_attacks *0
state.conditions.freestream.u = angle_of_attacks *0
state.conditions.freestream.v = angle_of_attacks *0
state.conditions.freestream.w = angle_of_attacks *0
state.conditions.static_stability.roll_rate = angle_of_attacks *0
state.conditions.static_stability.pitch_rate = angle_of_attacks *0
state.conditions.static_stability.yaw_rate = angle_of_attacks *0
state.conditions.frames.wind.transform_to_inertial = np.tile( np.array([[[1., 0., 0.],[0., 1., 0.],[0., 0., 1.]]]) , ( ctrl_pts, 1, 1) )
state.conditions.expand_rows(ctrl_pts)
state.conditions.control_surfaces = Data()
analyses.aerodynamics.aileron_flag = False
analyses.aerodynamics.rudder_flag = False
analyses.aerodynamics.elevator_flag = False
analyses.aerodynamics.flap_flag = False
analyses.aerodynamics.slat_flag = False
for wing in analyses.vehicle.wings:
for control_surface in wing.control_surfaces:
if type(control_surface) == RCAIDE.Library.Components.Wings.Control_Surfaces.Aileron:
analyses.aerodynamics.aileron_flag = True
state.conditions.control_surfaces.aileron = Data()
state.conditions.control_surfaces.aileron.deflection = control_surface.deflection * np.ones_like(angle_of_attacks)
state.conditions.control_surfaces.aileron.static_stability = Data()
state.conditions.control_surfaces.aileron.static_stability.coefficients = Data()
if type(control_surface) == RCAIDE.Library.Components.Wings.Control_Surfaces.Elevator:
analyses.aerodynamics.elevator_flag = True
state.conditions.control_surfaces.elevator = Data()
state.conditions.control_surfaces.elevator.deflection = control_surface.deflection * np.ones_like(angle_of_attacks)
state.conditions.control_surfaces.elevator.static_stability = Data()
state.conditions.control_surfaces.elevator.static_stability.coefficients = Data()
if type(control_surface) == RCAIDE.Library.Components.Wings.Control_Surfaces.Rudder:
analyses.aerodynamics.rudder_flag = True
state.conditions.control_surfaces.rudder = Data()
state.conditions.control_surfaces.rudder.deflection = control_surface.deflection * np.ones_like(angle_of_attacks)
state.conditions.control_surfaces.rudder.static_stability = Data()
state.conditions.control_surfaces.rudder.static_stability.coefficients = Data()
if type(control_surface) == RCAIDE.Library.Components.Wings.Control_Surfaces.Flap:
analyses.aerodynamics.flap_flag = True
state.conditions.control_surfaces.flap = Data()
state.conditions.control_surfaces.flap.deflection = control_surface.deflection * np.ones_like(angle_of_attacks)
state.conditions.control_surfaces.flap.static_stability = Data()
state.conditions.control_surfaces.flap.static_stability.coefficients = Data()
if type(control_surface) == RCAIDE.Library.Components.Wings.Control_Surfaces.Slat:
analyses.aerodynamics.slat_flag = True
state.conditions.control_surfaces.slat = Data()
state.conditions.control_surfaces.slat.deflection = control_surface.deflection * np.ones_like(angle_of_attacks)
state.conditions.control_surfaces.slat.static_stability = Data()
state.conditions.control_surfaces.slat.static_stability.coefficients = Data()
state.analyses = analyses
state.analyses.aerodynamics.filename = os.path.join(os.path.dirname(os.path.abspath(sys.argv[0])), "aerodynamic_training_data.pkl" )
state.analyses.aerodynamics.initialize(state.analyses.vehicle)
state.conditions.freestream.mach_number = mach_numbers
state.conditions.freestream.velocity = V
state.conditions.freestream.reynolds_number = non_dimensional_reynolds_numbers
state.conditions.frames.inertial.velocity_vector = np.tile(np.array([[0, 0, 0]]), ( ctrl_pts, 1))
state.conditions.frames.inertial.velocity_vector[:,0] = V[:,0]
_ = state.analyses.aerodynamics.evaluate(state,state.analyses.vehicle)
results = Data(
freestream = state.conditions.freestream,
aerodynamics = state.conditions.aerodynamics,
static_stability = state.conditions.static_stability,
dynamic_stability = state.conditions.dynamic_stability,
)
if type(state.analyses.aerodynamics) == RCAIDE.Framework.Analyses.Aerodynamics.Vortex_Lattice_Method:
results.vortex_distribution = state.analyses.aerodynamics.settings.vortex_distribution
return results
