Source code for RCAIDE.Library.Mission.Segments.Climb.Constant_Dynamic_Pressure_Constant_Angle
# RCAIDE/Library/Missions/Segments/Climb/Constant_Dynamic_Pressure_Constant_Angle.py
#
#
# Created: Jul 2023, M. Clarke
# ----------------------------------------------------------------------------------------------------------------------
# IMPORT
# ----------------------------------------------------------------------------------------------------------------------
# RCAIDE
import RCAIDE
# Package imports
import numpy as np
# ----------------------------------------------------------------------------------------------------------------------
# Initialize Conditions
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def initialize_conditions_unpack_unknowns(segment):
"""Sets the specified conditions which are given for the segment type.
Assumptions:
Constrant dynamic pressure and constant rate of climb
Source:
N/A
Inputs:
segment.climb_angle [radians]
segment.dynamic_pressure [pascals]
segment.altitude_start [meters]
segment.altitude_end [meters]
segment.state.numerics.dimensionless.control_points [unitless]
conditions.freestream.density [kilograms/meter^3]
Outputs:
conditions.frames.inertial.velocity_vector [meters/second]
conditions.frames.inertial.position_vector [meters]
conditions.frames.body.inertial_rotations [radians]
Properties Used:
N/A
"""
# unpack
climb_angle = segment.climb_angle
q = segment.dynamic_pressure
alt0 = segment.altitude_start
conditions = segment.state.conditions
beta = segment.sideslip_angle
rho = conditions.freestream.density[:,0]
# unpack unknowns
alts = conditions.frames.inertial.position_vector[:,2]
# Update freestream to get density
RCAIDE.Library.Mission.Common.Update.atmosphere(segment)
rho = conditions.freestream.density[:,0]
# 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]
# pack conditions
conditions.freestream.altitude[:,0] = -alts # positive altitude in this context
# check for initial velocity
if q is None:
if not segment.state.initials: raise AttributeError('dynamic pressure not set')
v_mag = np.linalg.norm(segment.state.initials.conditions.frames.inertial.velocity_vector[-1])
else:
# Update freestream to get density
RCAIDE.Library.Mission.Common.Update.atmosphere(segment)
rho = conditions.freestream.density[:,0]
# process velocity vector
v_mag = np.sqrt(2*q/rho)
v_x = np.cos(beta)*v_mag * np.cos(climb_angle)
v_y = np.sin(beta)*v_mag * np.cos(climb_angle)
v_z = -v_mag * np.sin(climb_angle)
# pack conditions
conditions.frames.inertial.velocity_vector[:,0] = v_x
conditions.frames.inertial.velocity_vector[:,1] = v_y
conditions.frames.inertial.velocity_vector[:,2] = v_z
[docs]
def residual_altitude(segment):
"""Computes the altitude residual
Assumptions:
No higher order terms.
Source:
N/A
Inputs:
segment.state.conditions.frames.inertial.total_force_vector [Newtons]
segment.state.conditions.frames.inertial.acceleration_vector [meter/second^2]
segment.state.conditions.weights.total_mass [kilogram]
segment.state.conditions.freestream.altitude [meter]
Outputs:
segment.state.residuals.altitude [meters]
Properties Used:
N/A
"""
# Unpack results
alt_in = segment.state.unknowns.altitude[:,0]
alt_out = segment.state.conditions.freestream.altitude[:,0]
segment.state.residuals.altitude[:,0] = (alt_in - alt_out)/alt_out[-1]
return
# ----------------------------------------------------------------------------------------------------------------------
# Update Differentials
# ----------------------------------------------------------------------------------------------------------------------
[docs]
def update_differentials(segment):
""" On each iteration creates the differentials and integration functions from knowns about the problem.
Sets the time at each point. Must return in dimensional time, with t[0] = 0.
This is different from the common method as it also includes the scaling of operators.
Assumptions:
Works with a segment discretized in vertical position, altitude
Inputs:
state.numerics.dimensionless.control_points [Unitless]
state.numerics.dimensionless.differentiate [Unitless]
state.numerics.dimensionless.integrate [Unitless]
state.conditions.frames.inertial.position_vector [meter]
state.conditions.frames.inertial.velocity_vector [meter/second]
Outputs:
state.conditions.frames.inertial.time [second]
"""
# unpack
numerics = segment.state.numerics
conditions = segment.state.conditions
x = numerics.dimensionless.control_points
D = numerics.dimensionless.differentiate
I = numerics.dimensionless.integrate
r = segment.state.conditions.frames.inertial.position_vector
v = segment.state.conditions.frames.inertial.velocity_vector
alt0 = segment.altitude_start
altf = segment.altitude_end
# 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]
dz = altf - alt0
vz = -v[:,2,None] # maintain column array
# get overall time step
dt = (dz/np.dot(I,vz))[-1]
# rescale operators
x = x * dt
D = D / dt
I = I * dt
# Calculate the altitudes
alt = np.dot(I,vz) + alt0
# pack
t_initial = segment.state.conditions.frames.inertial.time[0,0]
numerics.time.control_points = x
numerics.time.differentiate = D
numerics.time.integrate = I
conditions.frames.inertial.time[1:,0] = t_initial + x[1:,0]
conditions.frames.inertial.position_vector[:,2] = -alt[:,0]
conditions.freestream.altitude[:,0] = alt[:,0]
return
