Source code for RCAIDE.Library.Mission.Segments.Climb.Constant_Mach_Constant_Rate
# RCAIDE/Library/Missions/Segments/Climb/Constant_Mach_Constant_Rate.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE
from RCAIDE.Library.Mission.Common.Update.atmosphere import atmosphere
# Package imports
import numpy as np
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# Initialize Conditions
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[docs]
def initialize_conditions(segment):
"""
Initializes conditions for constant Mach climb with fixed rate
Parameters
----------
segment : Segment
The mission segment being analyzed
Notes
-----
This function sets up the initial conditions for a climb segment with constant
Mach number and constant rate of climb.
**Required Segment Components**
segment:
- climb_rate : float
Rate of climb [m/s]
- mach_number : float
Mach number to maintain [-]
- altitude_start : float
Initial altitude [m]
- altitude_end : float
Final altitude [m]
- sideslip_angle : float
Aircraft sideslip angle [rad]
- state:
numerics.dimensionless.control_points : array
Discretization points [-]
conditions : Data
State conditions container
- analyses:
atmosphere : Model
Atmospheric model for property calculations
**Calculation Process**
1. Discretize altitude profile
2. Get atmospheric properties for speed of sound
3. Calculate true airspeed from Mach number
4. Decompose velocity into components using:
- Fixed climb rate
- Sideslip angle
- Constant Mach requirement
**Major Assumptions**
* Constant Mach number
* Constant rate of climb
* Standard atmosphere model
* Small angle approximations
* Quasi-steady flight
Returns
-------
None
Updates segment conditions directly:
- conditions.frames.inertial.velocity_vector [m/s]
- conditions.frames.inertial.position_vector [m]
- conditions.freestream.altitude [m]
See Also
--------
RCAIDE.Framework.Mission.Segments
RCAIDE.Library.Mission.Common.Update.atmosphere
"""
# unpack
# unpack User Inputs
climb_rate = segment.climb_rate
mach_number = segment.mach_number
alt0 = segment.altitude_start
altf = segment.altitude_end
beta = segment.sideslip_angle
t_nondim = segment.state.numerics.dimensionless.control_points
conditions = segment.state.conditions
# check for initial altitude
if alt0 is None:
if not segment.state.initials: raise AttributeError('initial altitude not set')
alt0 = -1.0 * segment.state.initials.conditions.frames.inertial.position_vector[-1,2]
# discretize on altitude
alt = t_nondim * (altf-alt0) + alt0
conditions.freestream.altitude[:,0] = alt[:,0] # positive altitude in this context
# Update freestream to get speed of sound
atmosphere(segment)
a = conditions.freestream.speed_of_sound
# check for initial velocity
if mach_number is None:
if not segment.state.initials: raise AttributeError('mach not set')
v_mag = np.linalg.norm(segment.state.initials.conditions.frames.inertial.velocity_vector[-1])
else:
# process velocity vector
v_mag = mach_number * a
v_z = -climb_rate # z points down
v_xy = np.sqrt( v_mag**2 - v_z**2 )
v_x = np.cos(beta)*v_xy
v_y = np.sin(beta)*v_xy
# pack conditions
conditions.frames.inertial.velocity_vector[:,0] = v_x[:,0]
conditions.frames.inertial.velocity_vector[:,1] = v_y[:,0]
conditions.frames.inertial.velocity_vector[:,2] = v_z
conditions.frames.inertial.position_vector[:,2] = -alt[:,0] # z points down
conditions.freestream.altitude[:,0] = alt[:,0] # positive altitude in this context
