Gravity update foundation

aviary/constants.py

@@ -2,9 +2,36 @@
 
 units.add_unit('distance_units', '1*m')
 
+GRAV_EARTH = (
+    9.80665,
+    'm/s**2',
+)  # NIST https://physics.nist.gov/cgi-bin/cuu/Value?gn|search_for=gravity
+GRAV_MARS = (
+    3.712,
+    'm/s**2',
+)  # Mars Global Reference Atmospheric Model (Mars-GRAM) 2024: User Guide, NASA/TM-20240012934
+GRAV_VENUS = (
+    8.870,
+    'm/s**2',
+)  # Venus Global Reference Atmospheric Model (Venus-GRAM): User Guide, NASA/TM-20210022168
+
+# RADIUS_EARTH = (6371009, 'm')  # Source: GRS80, mean earth radius (rounded to nearest meter)
+RADIUS_EARTH = (6356766, 'm')  # TODO remove and replace with above
+
+# RADIUS_MARS = (
+#     3386200,
+#     'm',
+# )  # Mars Global Reference Atmospheric Model (Mars-GRAM) 2024: User Guide, NASA/TM-20240012934, avg of equatorial and polar radius
+RADIUS_MARS = (3396200, 'm')  # TODO remove and replace with above
+RADIUS_VENUS = (
+    6051800,
+    'm',
+)  # Venus Global Reference Atmospheric Model (Venus-GRAM): User Guide, NASA/TM-20210022168, avg of equatorial and polar radius
+
+GNS = 9.8236930  # grav_accel_at_surface_earth # remove this asap
 GRAV_METRIC_GASP = 9.81  # m/s^2
-GRAV_ENGLISH_GASP = 32.2  # ft/s^2
 GRAV_METRIC_FLOPS = 9.80665  # m/s^2
+GRAV_ENGLISH_GASP = 32.2  # ft/s^2
 GRAV_ENGLISH_FLOPS = 32.17399  # ft/s^2
 GRAV_ENGLISH_LBM = 1.0  # lbf/lbm
 # See issue 1169 for the value of RHO_SEA_LEVEL_ENGLISH

aviary/interface/test/sizing_results_for_test.json

@@ -1124,6 +1124,18 @@
         "unitless",
         "<class 'float'>"
     ],
+    [
+        "settings:atmosphere_model",
+        "STANDARD",
+        "unitless",
+        "<enum 'AtmosphereModel'>"
+    ],
+    [
+        "mission:gravity",
+        9.80665,
+        "m/s**2",
+        "<class 'float'>"
+    ],
     [
         "mission:gross_mass",
         175400.0,

aviary/subsystems/atmosphere/atmosphere.py

@@ -1,23 +1,10 @@
 import numpy as np
 import openmdao.api as om
 
-from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Cold import atm_data as cold_210A
-from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Hot import atm_data as hot_210A
-from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Polar import atm_data as polar_210A
-from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Tropical import atm_data as tropical_210A
-from aviary.subsystems.atmosphere.data.StandardAtm1976 import atm_data as USatm1976
-from aviary.subsystems.atmosphere.data.MarsReference2024 import atm_data as MarsReference2024
-from aviary.subsystems.atmosphere.data.MarsHellasHot import atm_data as MarsHellasHot
-from aviary.subsystems.atmosphere.data.MarsHellasCold import atm_data as MarsHellasCold
-from aviary.subsystems.atmosphere.data.MarsEquatorHot import atm_data as MarsEquatorHot
-from aviary.subsystems.atmosphere.data.MarsEquatorCold import atm_data as MarsEquatorCold
-from aviary.subsystems.atmosphere.data.MarsPolarHot import atm_data as MarsPolarHot
-from aviary.subsystems.atmosphere.data.MarsPolarCold import atm_data as MarsPolarCold
-from aviary.subsystems.atmosphere.data.VenusReference2021 import atm_data as VenusReference2021
 from aviary.subsystems.atmosphere.flight_conditions import FlightConditions
 from aviary.variable_info.enums import AtmosphereModel, SpeedType
-from aviary.variable_info.functions import add_aviary_option
 from aviary.variable_info.variables import Dynamic, Settings
+from aviary.subsystems.atmosphere.utils.get_atmosphere_data import get_atmosphere_data
 
 
 class Atmosphere(om.Group):
@@ -117,60 +104,26 @@ def setup(self):
 
         self._dt = self.options['delta_T_Celcius']
 
-        self._R0 = 0  # instantiate and add correct value later
+        self.source_data, self.planet, planet_radius, _ = get_atmosphere_data(
+            self.options[Settings.ATMOSPHERE_MODEL]
+        )
+
+        self._R0 = planet_radius[0]  # in meters
+
         self._geometric = self.options['h_def'] == 'geometric'
         # From the U.S. Standard Atmosphere 1976 publication located here
         # https://www.ngdc.noaa.gov/stp/space-weather/online-publications/miscellaneous/us-standard-atmosphere-1976/us-standard-atmosphere_st76-1562_noaa.pdf
 
         Rs = 8314.32  # J/(kmol*K), Ideal Gas constant
-
-        if self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.STANDARD:
-            self.source_data = USatm1976
-            self.planet = 'Earth'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.TROPICAL:
-            self.source_data = tropical_210A
-            self.planet = 'Earth'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.POLAR:
-            self.source_data = polar_210A
-            self.planet = 'Earth'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.HOT:
-            self.source_data = hot_210A
-            self.planet = 'Earth'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.COLD:
-            self.source_data = cold_210A
-            self.planet = 'Earth'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_REFERENCE:
-            self.source_data = MarsReference2024
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_HELLAS_HOT:
-            self.source_data = MarsHellasHot
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_HELLAS_COLD:
-            self.source_data = MarsHellasCold
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_EQUATOR_HOT:
-            self.source_data = MarsEquatorHot
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_EQUATOR_COLD:
-            self.source_data = MarsEquatorCold
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_POLAR_HOT:
-            self.source_data = MarsPolarHot
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.MARS_POLAR_COLD:
-            self.source_data = MarsPolarCold
-            self.planet = 'Mars'
-        elif self.options[Settings.ATMOSPHERE_MODEL] is AtmosphereModel.VENUS_REFERENCE:
-            self.source_data = VenusReference2021
-            self.planet = 'Venus'
+        M_air = 0  #
+        gamma = 0  #
 
         # The constants below are used as a simplification to enable calculation of properties not given by by source data tables
         if self.planet == 'Earth':
             M_air = 28.97  # (kg/kmol), molar mass of dry air on Earth
             gamma = 1.4  # Ratio of specific heats
             self._S = 110.4  # (K) Southerlands constant for Earth air
             self._beta = 1.458e-6  # (s*m*K**(1/2)) viscosity scaling coefficient
-            self._R0 = 6_356_766  # (meters) The effective Earth Radius
         elif self.planet == 'Mars':
             M_air = 43.34  # (kg/kmol), mean molar mass of Mars atmosphere https://descanso.jpl.nasa.gov/propagation/mars/MarsPub_sec4.pdf
             gamma = 1.36  # Ratio of specific heats, Based on averaging values from Hellas_summar, Hellas_winter, Equatorial_summar,
@@ -180,7 +133,6 @@ def setup(self):
             self._beta = 1.503e-6  # (s*m*K**(1/2)) viscosity scaling coefficient calculated from other constants listed for C02
             # https://doc.comsol.com/5.6/doc/com.comsol.help.cfd/cfd_ug_fluidflow_high_mach.08.27.html
             # Calculated via the equation: self_beta = 1.370**10-5 * (273+self._S)/273**(3/2)
-            self._R0 = 3_396_200  # (meters) Mean Equatorial Radius of Mars
         elif self.planet == 'Venus':
             # 96% CO2 atmosphere
             M_air = 43.45  # (kg/kmol) Venus, 12 Apr 2024, by Cedric Gillmann et al. https://arxiv.org/html/2404.07669v2
@@ -189,7 +141,6 @@ def setup(self):
             self._S = 222  # (K) we use the constant for CO2 which is simillar to Mars because this atmosphere is primarily driven by CO2 interaction.
             self._beta = 1.503e-6  # (s*m*K**(1/2)) viscosity scaling coefficient calculated from other constants listed for C02, the same way as was done for Mars
             # the only input the the equation os self._S so this result is the same as Mars
-            self._R0 = 6_051_800  # (meters) Mean Equatorial Radius
 
         self._R_air = Rs / M_air  # (J/ (kg * K)), gas constant for atmosphere
         self._K = gamma * Rs / M_air  # (J/(kg * K))

aviary/subsystems/atmosphere/utils/get_atmosphere_data.py

@@ -0,0 +1,59 @@
+from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Cold import atm_data as cold_210A
+from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Hot import atm_data as hot_210A
+from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Polar import atm_data as polar_210A
+from aviary.subsystems.atmosphere.data.MIL_SPEC_210A_Tropical import atm_data as tropical_210A
+from aviary.subsystems.atmosphere.data.StandardAtm1976 import atm_data as USatm1976
+from aviary.subsystems.atmosphere.data.MarsReference2024 import atm_data as MarsReference2024
+from aviary.subsystems.atmosphere.data.MarsHellasHot import atm_data as MarsHellasHot
+from aviary.subsystems.atmosphere.data.MarsHellasCold import atm_data as MarsHellasCold
+from aviary.subsystems.atmosphere.data.MarsEquatorHot import atm_data as MarsEquatorHot
+from aviary.subsystems.atmosphere.data.MarsEquatorCold import atm_data as MarsEquatorCold
+from aviary.subsystems.atmosphere.data.MarsPolarHot import atm_data as MarsPolarHot
+from aviary.subsystems.atmosphere.data.MarsPolarCold import atm_data as MarsPolarCold
+from aviary.subsystems.atmosphere.data.VenusReference2021 import atm_data as VenusReference2021
+from aviary.variable_info.enums import AtmosphereModel
+from aviary.constants import (
+    RADIUS_EARTH,
+    RADIUS_MARS,
+    RADIUS_VENUS,
+    GRAV_EARTH,
+    GRAV_MARS,
+    GRAV_VENUS,
+)
+
+
+def get_atmosphere_data(atmosphere_model):
+    """
+    Return the atmosphere source data, planet name, and gravitational constant
+    associated with the requested atmosphere model.
+
+    Parameters
+    ----------
+    atmosphere_model : AtmosphereModel
+        Atmosphere model enum.
+
+    Returns
+    -------
+    tuple
+        (source_data, planet, gravity)
+    """
+    atmosphere_lookup = {
+        AtmosphereModel.STANDARD: (USatm1976, 'Earth', RADIUS_EARTH, GRAV_EARTH),
+        AtmosphereModel.TROPICAL: (tropical_210A, 'Earth', RADIUS_EARTH, GRAV_EARTH),
+        AtmosphereModel.POLAR: (polar_210A, 'Earth', RADIUS_EARTH, GRAV_EARTH),
+        AtmosphereModel.HOT: (hot_210A, 'Earth', RADIUS_EARTH, GRAV_EARTH),
+        AtmosphereModel.COLD: (cold_210A, 'Earth', RADIUS_EARTH, GRAV_EARTH),
+        AtmosphereModel.MARS_REFERENCE: (MarsReference2024, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_HELLAS_HOT: (MarsHellasHot, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_HELLAS_COLD: (MarsHellasCold, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_EQUATOR_HOT: (MarsEquatorHot, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_EQUATOR_COLD: (MarsEquatorCold, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_POLAR_HOT: (MarsPolarHot, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.MARS_POLAR_COLD: (MarsPolarCold, 'Mars', RADIUS_MARS, GRAV_MARS),
+        AtmosphereModel.VENUS_REFERENCE: (VenusReference2021, 'Venus', RADIUS_VENUS, GRAV_VENUS),
+    }
+
+    try:
+        return atmosphere_lookup[atmosphere_model]
+    except KeyError:
+        raise ValueError(f'Could not find {atmosphere_model} in get_atmosphere_data().')

aviary/utils/preprocessors.py

@@ -92,6 +92,21 @@ def preprocess_options(
         ):
             aviary_options.set_val(Aircraft.Design.PERCENT_EXCRESCENCE_DRAG, 0.06)
 
+    # preprocess atmosphere / GRAV??
+    # Set the gravity model based on the atmosphere model to enable calculation of weight from mass
+    from aviary.subsystems.atmosphere.utils.get_atmosphere_data import get_atmosphere_data
+
+    if Settings.ATMOSPHERE_MODEL not in aviary_options:
+        aviary_options.set_val(
+            Settings.ATMOSPHERE_MODEL, meta_data[Settings.ATMOSPHERE_MODEL]['default_value']
+        )
+    _, _, _, planet_gravity = get_atmosphere_data(aviary_options.get_val(Settings.ATMOSPHERE_MODEL))
+    if Mission.GRAVITY not in aviary_options:  # Check to see if the user has set a gravity profile.
+        # No gravity profile is set, set it now.
+        aviary_options.set_val(
+            Mission.GRAVITY, val=planet_gravity[0], units=planet_gravity[1]
+        )  # contains both value and units as a tuple.
+
 
 def preprocess_crewpayload(aviary_options: AviaryValues, meta_data=CoreMetaData, verbosity=None):
     """

aviary/variable_info/variable_meta_data.py

@@ -6892,6 +6892,17 @@
     'specifies a taxi phase as part of the regular mission phases.',
 )
 
+add_meta_data(
+    Mission.GRAVITY,
+    meta_data=_MetaData,
+    historical_name={'GASP': None, 'FLOPS': None},
+    desc='Gravitational acceleration of the planet.',
+    types=float,
+    option=True,
+    # The default gravity model is set based on Settings.ATMOSPHERE_MODEL
+    units='m/s**2',
+)
+
 add_meta_data(
     Mission.GROSS_MASS,
     meta_data=_MetaData,

aviary/variable_info/variables.py

@@ -676,6 +676,7 @@ class Mission:
     FINAL_MASS = 'mission:final_mass'
     FINAL_TIME = 'mission:final_time'
     FUEL_MASS = 'mission:fuel_mass'
+    GRAVITY = 'mission:gravity'
     GROSS_MASS = 'mission:gross_mass'
     OPERATING_ITEMS_MASS = 'mission:operating_items_mass'
     OPERATING_ITEMS_MASS_ADDITIONAL = 'mission:operating_items_mass_additional'