# RCAIDE/Compoments/Nacelles/Nacelle.py
#
# Created: Mar 2024, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE imports
import RCAIDE
from RCAIDE.Framework.Core import Data
from RCAIDE.Library.Components import Component
import scipy as sp
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Nacelle
# ----------------------------------------------------------------------------------------------------------------------
[docs]
class Nacelle(Component):
"""
Base class for aircraft engine nacelles providing core functionality for geometric
definition and analysis.
Attributes
----------
tag : str
Unique identifier for the nacelle component, defaults to 'nacelle'
origin : list
3D coordinates [x, y, z] defining the nacelle's reference point,
defaults to [[0.0, 0.0, 0.0]]
aerodynamic_center : list
3D coordinates [x, y, z] of the nacelle's aerodynamic center,
defaults to [0.0, 0.0, 0.0]
areas : Data
Collection of nacelle area measurements
- front_projected : float
Frontal area, defaults to 0.0
- side_projected : float
Side profile area, defaults to 0.0
- wetted : float
Total wetted surface area, defaults to 0.0
diameter : float
Maximum diameter of the nacelle, defaults to 0.0
inlet_diameter : float
Diameter of the engine inlet, defaults to 0.0
length : float
Total length of the nacelle, defaults to 0.0
orientation_euler_angles : list
Rotation angles [roll, pitch, yaw] in radians, defaults to [0.0, 0.0, 0.0]
flow_through : bool
Flag indicating if nacelle has flow passing through it, defaults to True
has_pylon : bool
Flag indicating if nacelle is mounted on a pylon, defaults to True
differential_pressure : float
Pressure differential between internal and external flow, defaults to 0.0
cowling_airfoil_angle : float
Angle of the cowling lip airfoil section, defaults to 0.0
Notes
-----
The nacelle class provides the foundation for engine installation design, including:
* Geometric definition capabilities
* Coordinate transformation utilities
* Integration with propulsion system analysis
**Major Assumptions**
* Rigid body for structural analysis
* Quasi-steady aerodynamics
**Definitions**
'Nacelle Frame'
Local coordinate system with X out the nose, Z towards the ground,
and Y out the right side
'Vehicle Frame'
Aircraft coordinate system with X towards the tail, Z towards the ceiling,
and Y out the right wing
See Also
--------
RCAIDE.Library.Components.Nacelles.Body_of_Revolution_Nacelle
Implementation for axisymmetric nacelles
RCAIDE.Library.Components.Nacelles.Stack_Nacelle
Implementation for stacked segment nacelles
"""
def __defaults__(self):
"""
Sets default values for the nacelle attributes.
"""
self.tag = 'nacelle'
self.origin = [[0.0,0.0,0.0]]
self.aerodynamic_center = [0.0,0.0,0.0]
self.areas = Data()
self.areas.front_projected = 0.0
self.areas.side_projected = 0.0
self.areas.wetted = 0.0
self.diameter = 0.0
self.inlet_diameter = 0.0
self.length = 0.0
self.orientation_euler_angles = [0.,0.,0.]
self.flow_through = True
self.has_pylon = True
self.differential_pressure = 0.0
self.cowling_airfoil_angle = 0.0
[docs]
def append_operating_conditions(self, segment, energy_conditions, noise_conditions=None):
"""
Placeholder for adding operating conditions to the nacelle.
Parameters
----------
segment : Data
Flight segment data
propulsor : Data
Propulsion system data
"""
energy_conditions[self.tag] = RCAIDE.Framework.Mission.Common.Conditions()
return
[docs]
def nac_vel_to_body(self):
"""
Computes rotation matrix from nacelle velocity frame to body frame.
Returns
-------
ndarray
3x3 rotation matrix
Notes
-----
Assumes two nacelle frames:
* Vehicle frame describing location
* Velocity frame for aerodynamic calculations
"""
body2nacvel = self.body_to_nac_vel()
r = sp.spatial.transform.Rotation.from_matrix(body2nacvel)
r = r.inv()
rot_mat = r.as_matrix()
return rot_mat
[docs]
def body_to_nac_vel(self):
"""
Computes rotation matrix from body frame to nacelle velocity frame.
Returns
-------
ndarray
3x3 rotation matrix
Notes
-----
Transformation sequence:
1. Body to vehicle frame
2. Vehicle to nacelle vehicle frame
3. Nacelle vehicle to nacelle velocity frame
"""
# Go from body to vehicle frame
body_2_vehicle = sp.spatial.transform.Rotation.from_rotvec([0,np.pi,0]).as_matrix()
# Go from vehicle frame to nacelle vehicle frame
rots = np.array(self.orientation_euler_angles) * 1.
vehicle_2_nac_vec = sp.spatial.transform.Rotation.from_rotvec(rots).as_matrix()
# Go from nacelle vehicle frame to nacelle velocity frame
nac_vec_2_nac_vel = self.vec_to_vel()
# Combine transformations
rot1 = np.matmul(body_2_vehicle,vehicle_2_nac_vec)
rot_mat = np.matmul(rot1,nac_vec_2_nac_vel)
return rot_mat
[docs]
def vec_to_vel(self):
"""
Computes rotation matrix from nacelle vehicle frame to nacelle velocity frame.
Returns
-------
ndarray
3x3 rotation matrix
"""
rot_mat = sp.spatial.transform.Rotation.from_rotvec([0,np.pi,0]).as_matrix()
return rot_mat
