Note
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Case 10: Sphere launched ballistically northward along Prime Meridian
Verifies |
Coriolis |
Gravitation |
J2 |
Geodesy |
WGS-84 rotating |
Atmosphere |
US 1976 STD |
Winds |
still air |
Vehicle |
Sphere with constant \(C_D\) |
Notes |
Initial velocity is \(\sqrt{2000}\) ft/s aligned 45 degrees from vertical, heading north; zero angular rate relative to launch platform. |
from simupy.block_diagram import BlockDiagram
import simupy_flight
import numpy as np
from nesc_testcase_helper import plot_nesc_comparisons, int_opts, benchmark
from nesc_testcase_helper import ft_per_m, kg_per_slug
Ixx = 3.6 * kg_per_slug / (ft_per_m**2) # slug-ft2
Iyy = 3.6 * kg_per_slug / (ft_per_m**2) # slug-ft2
Izz = 3.6 * kg_per_slug / (ft_per_m**2) # slug-ft2
Ixy = 0.0 * kg_per_slug / (ft_per_m**2) # slug-ft2
Iyz = 0.0 * kg_per_slug / (ft_per_m**2) # slug-ft2
Izx = 0.0 * kg_per_slug / (ft_per_m**2) # slug-ft2
m = 1.0 * kg_per_slug # slug
x = 0.0
y = 0.0
z = 0.0
S_A = 0.1963495 / (ft_per_m**2)
b_l = 1.0
c_l = 1.0
a_l = b_l
lat_ic = 0.0 * np.pi / 180
long_ic = 0.0 * np.pi / 180
h_ic = 0.0 / ft_per_m
V_N_ic = 1000.0 / ft_per_m
V_E_ic = 000.0 / ft_per_m
V_D_ic = -1000.0 / ft_per_m
psi_ic = 0.0 * np.pi / 180
theta_ic = 0.0 * np.pi / 180
phi_ic = 0.0 * np.pi / 180
p_b_ic = 0.0 * np.pi / 180
q_b_ic = 0.0 * np.pi / 180
r_b_ic = 0.0 * np.pi / 180
# omega_X_ic = 0.004178073*np.pi/180
# omega_Y_ic = 0.*np.pi/180
# omega_Z_ic = 0.*np.pi/180
planet = simupy_flight.Planet(
gravity=simupy_flight.earth_J2_gravity,
winds=simupy_flight.get_constant_winds(),
atmosphere=simupy_flight.atmosphere_1976,
planetodetics=simupy_flight.Planetodetic(
a=simupy_flight.earth_equitorial_radius,
omega_p=simupy_flight.earth_rotation_rate,
f=simupy_flight.earth_f,
),
)
vehicle = simupy_flight.Vehicle(
base_aero_coeffs=simupy_flight.get_constant_aero(CD_b=0.1),
m=m,
I_xx=Ixx,
I_yy=Iyy,
I_zz=Izz,
I_xy=Ixy,
I_yz=Iyz,
I_xz=Izx,
x_com=x,
y_com=y,
z_com=z,
x_mrc=x,
y_mrc=y,
z_mrc=z,
S_A=S_A,
a_l=a_l,
b_l=b_l,
c_l=c_l,
d_l=0.0,
)
BD = BlockDiagram(planet, vehicle)
BD.connect(planet, vehicle, inputs=np.arange(planet.dim_output))
BD.connect(vehicle, planet, inputs=np.arange(vehicle.dim_output))
planet.initial_condition = planet.ic_from_planetodetic(
lamda_D=long_ic,
phi_D=lat_ic,
h=h_ic,
V_N=V_N_ic,
V_E=V_E_ic,
V_D=V_D_ic,
psi=psi_ic,
theta=theta_ic,
phi=phi_ic,
p_B=p_b_ic,
q_B=q_b_ic,
r_B=r_b_ic,
)
# planet.initial_condition[-3:] = omega_X_ic, omega_Y_ic, omega_Z_ic
planet.initial_condition[-2] = 0.0
with benchmark() as b:
res = BD.simulate(30, integrator_options=int_opts)
time to simulate: 1.669 s
plot_nesc_comparisons(res, "10")
Total running time of the script: (0 minutes 6.076 seconds)