Remove Wing area from Simple Landing builder defaults

aviary/mission/energy_state/phases/build_landing.py

@@ -1,41 +1,9 @@
 import openmdao.api as om
 
 from aviary.mission.energy_state.phases.simplified_landing import LandingGroup
-from aviary.variable_info.variables import Aircraft, Mission
 
 
 class Landing:
-    """
-    Define user constraints for a climb phase.
-
-    Parameters
-    ----------
-    ref_wing_area : float (0.0)
-        reference are of wing (ft^2)
-    Cl_max_ldg : float (None)
-        maximum coefficient of lift in landing configuration (None)
-
-    Returns
-    -------
-    Group
-        a Group object in OpenMDAO
-    """
-
-    def __init__(
-        self,
-        ref_wing_area=None,
-        Cl_max_ldg=None,
-    ):
-        self.ref_wing_area = ref_wing_area  # ft**2
-        self.Cl_max_ldg = Cl_max_ldg  # no units
-        # note: need to clean this up so that some of these variables come from
-        # connections.
-
-    __slots__ = (
-        'ref_wing_area',
-        'Cl_max_ldg',
-    )
-
     def build_phase(self, use_detailed=False):
         """
         Construct and return a new phase for landing analysis.
@@ -56,15 +24,8 @@ def build_phase(self, use_detailed=False):
                 'Must set landing method to `use_detailed=False`, detailed landing is'
                 ' not currently enabled.'
             )
-
-        ##############
-        # Add Inputs #
-        ##############
-
-        landing = LandingGroup()
-        landing.set_input_defaults(Aircraft.Wing.AREA, val=self.ref_wing_area, units='ft**2')
-        landing.set_input_defaults(
-            Mission.Landing.LIFT_COEFFICIENT_MAX, val=self.Cl_max_ldg, units='unitless'
-        )
+        else:
+            # Simple landing group
+            landing = LandingGroup()
 
         return landing

aviary/mission/energy_state/phases/simplified_landing.py

@@ -1,6 +1,6 @@
 import openmdao.api as om
 
-from aviary.constants import GRAV_ENGLISH_LBM, RHO_SEA_LEVEL_METRIC
+from aviary.constants import GRAV_ENGLISH_LBM, RHO_SEA_LEVEL_ENGLISH
 from aviary.subsystems.atmosphere.atmosphere import Atmosphere
 from aviary.variable_info.functions import add_aviary_input, add_aviary_output
 from aviary.variable_info.variables import Aircraft, Dynamic, Mission
@@ -10,36 +10,19 @@ class LandingCalc(om.ExplicitComponent):
     """Calculate the distance covered over the ground and approach velocity during landing."""
 
     def setup(self):
-        add_aviary_input(self, Mission.FINAL_MASS, val=150_000)
-
-        add_aviary_input(
-            self,
-            Dynamic.Atmosphere.DENSITY,
-            val=1.225,
-            units='kg/m**3',
-            desc='atmospheric density',
-        )
-
-        add_aviary_input(self, Aircraft.Wing.AREA, val=700)
-
-        add_aviary_input(self, Mission.Landing.LIFT_COEFFICIENT_MAX, val=3)
+        add_aviary_input(self, Mission.FINAL_MASS, units='lbm')
+        add_aviary_input(self, Dynamic.Atmosphere.DENSITY, units='slug/ft**3')
+        add_aviary_input(self, Aircraft.Wing.AREA, units='ft**2')
+        add_aviary_input(self, Mission.Landing.LIFT_COEFFICIENT_MAX, units='unitless')
 
-        add_aviary_output(self, Mission.Landing.GROUND_DISTANCE, val=0)
+        add_aviary_output(self, Mission.Landing.GROUND_DISTANCE, units='ft')
+        add_aviary_output(self, Mission.Landing.INITIAL_VELOCITY, units='ft/s')
 
-        add_aviary_output(self, Mission.Landing.INITIAL_VELOCITY, val=0)
-
-        self.declare_partials(
-            Mission.Landing.INITIAL_VELOCITY,
-            [
-                Mission.Landing.LIFT_COEFFICIENT_MAX,
-                Aircraft.Wing.AREA,
-                Mission.FINAL_MASS,
-            ],
-        )
+        self.declare_partials(Mission.Landing.INITIAL_VELOCITY, '*')
         self.declare_partials(Mission.Landing.GROUND_DISTANCE, '*')
 
     def compute(self, inputs, outputs):
-        rho_SL = RHO_SEA_LEVEL_METRIC
+        rho_SL = RHO_SEA_LEVEL_ENGLISH
         landing_weight = inputs[Mission.FINAL_MASS] * GRAV_ENGLISH_LBM
         rho = inputs[Dynamic.Atmosphere.DENSITY]
         planform_area = inputs[Aircraft.Wing.AREA]
@@ -51,14 +34,16 @@ def compute(self, inputs, outputs):
         # distance covered during landing, which should be less.
 
         Cl_app = Cl_ldg_max / 1.3**2
-        V_app = 17.18644 * (landing_weight / (planform_area * Cl_app)) ** 0.5
+
+        V_app = ((2 * landing_weight) / (rho * planform_area * Cl_app)) ** 0.5
+
         landing_distance = 2500 + 105 * landing_weight / (planform_area * rho_ratio * Cl_app * 1.69)
 
         outputs[Mission.Landing.GROUND_DISTANCE] = landing_distance
         outputs[Mission.Landing.INITIAL_VELOCITY] = V_app
 
     def compute_partials(self, inputs, J):
-        rho_SL = RHO_SEA_LEVEL_METRIC
+        rho_SL = RHO_SEA_LEVEL_ENGLISH
         landing_weight = inputs[Mission.FINAL_MASS] * GRAV_ENGLISH_LBM
         rho = inputs[Dynamic.Atmosphere.DENSITY]
         planform_area = inputs[Aircraft.Wing.AREA]
@@ -68,29 +53,27 @@ def compute_partials(self, inputs, J):
 
         Cl_app = Cl_ldg_max / 1.3**2
 
-        J[Mission.Landing.INITIAL_VELOCITY, Mission.Landing.LIFT_COEFFICIENT_MAX] = (
-            17.18644
-            * 0.5
-            * (landing_weight / (planform_area * Cl_app)) ** (-0.5)
-            * (-landing_weight)
-            / (planform_area * Cl_app**2)
-            / 1.3**2
+        # INITIAL_VELOCITY (V_app) Partials
+        V_app = ((2 * landing_weight) / (rho * planform_area * Cl_app)) ** 0.5
+        d_sqrt = 0.5 / V_app
+
+        J[Mission.Landing.INITIAL_VELOCITY, Mission.FINAL_MASS] = (
+            d_sqrt * (2 * GRAV_ENGLISH_LBM) / (rho * planform_area * Cl_app)
+        )
+
+        J[Mission.Landing.INITIAL_VELOCITY, Dynamic.Atmosphere.DENSITY] = (
+            d_sqrt * (-2 * landing_weight) / (rho**2 * planform_area * Cl_app)
         )
+
         J[Mission.Landing.INITIAL_VELOCITY, Aircraft.Wing.AREA] = (
-            17.18644
-            * 0.5
-            * (landing_weight / (planform_area * Cl_app)) ** (-0.5)
-            * (-landing_weight)
-            / (planform_area**2 * Cl_app)
+            d_sqrt * (-2 * landing_weight) / (rho * planform_area**2 * Cl_app)
         )
-        J[Mission.Landing.INITIAL_VELOCITY, Mission.FINAL_MASS] = (
-            17.18644
-            * 0.5
-            * (landing_weight / (planform_area * Cl_app)) ** (-0.5)
-            * GRAV_ENGLISH_LBM
-            / (planform_area * Cl_app)
+
+        J[Mission.Landing.INITIAL_VELOCITY, Mission.Landing.LIFT_COEFFICIENT_MAX] = (
+            d_sqrt * (-2 * landing_weight) / (rho * planform_area * Cl_app**2) / 1.3**2
         )
 
+        # GROUND DISTANCE Partials:
         J[Mission.Landing.GROUND_DISTANCE, Mission.FINAL_MASS] = (
             105 * GRAV_ENGLISH_LBM / (planform_area * rho_ratio * Cl_app * 1.69)
         )
@@ -107,8 +90,8 @@ def compute_partials(self, inputs, J):
 
 class LandingGroup(om.Group):
     """
-    Calculate the distance covered over the ground and approach velocity
-    during landing with atmosphere is included.
+    Calculate the estimated Landing field length and velocity given the aircraft properties and atmospheric conditions.
+    Note this is not the actual distance covered over the ground.
     """
 
     def setup(self):

aviary/mission/energy_state/phases/test/test_building_landing.py

@@ -5,24 +5,25 @@
 from openmdao.utils.testing_utils import use_tempdirs
 
 from aviary.mission.energy_state.phases.build_landing import Landing
-from aviary.variable_info.variables import Mission
+from aviary.variable_info.variables import Aircraft, Mission
 
 
 @use_tempdirs
 class LandingPhaseTest(unittest.TestCase):
     """Test landing phase builder."""
 
     def test_case1(self):
-        landing_options = Landing(
-            ref_wing_area=1370.0,  # ft**2
-            Cl_max_ldg=3,  # no units
-        )
+        landing_options = Landing()
 
         use_detailed = False
         landing = landing_options.build_phase(use_detailed=use_detailed)
 
         prob = om.Problem()
         prob.model = landing
+        prob.model.set_input_defaults(Mission.FINAL_MASS, val=150000.0, units='lbm')
+        prob.model.set_input_defaults(Mission.Landing.INITIAL_ALTITUDE, val=0, units='ft')
+        prob.model.set_input_defaults(Aircraft.Wing.AREA, val=1370.0, units='ft**2')
+        prob.model.set_input_defaults(Mission.Landing.LIFT_COEFFICIENT_MAX, val=3, units='unitless')
         prob.setup(force_alloc_complex=True)
         prob.run_model()
         partial_data = prob.check_partials(
@@ -31,8 +32,10 @@ def test_case1(self):
         assert_check_partials(partial_data, atol=1e-12, rtol=1e-12)
 
         tol = 1e-6
-        assert_near_equal(prob[Mission.Landing.GROUND_DISTANCE], 6332.4878059, tol)
-        assert_near_equal(prob[Mission.Landing.INITIAL_VELOCITY], 134.9752, tol)
+        assert_near_equal(prob[Mission.Landing.GROUND_DISTANCE], 6332.13214907, tol)
+        assert_near_equal(
+            prob.get_val(Mission.Landing.INITIAL_VELOCITY, units='kn'), 134.97550621, tol
+        )
 
 
 if __name__ == '__main__':

aviary/mission/energy_state/phases/test/test_simplified_landing.py

@@ -21,20 +21,14 @@ def setUp(self):
             promotes=['*'],
         )
 
+        self.prob.model.set_input_defaults(Mission.FINAL_MASS, val=152800.0, units='lbm')
         self.prob.model.set_input_defaults(
-            Mission.FINAL_MASS, val=152800.0, units='lbm'
-        )  # check (this is the design landing mass)
-        self.prob.model.set_input_defaults(
-            Dynamic.Atmosphere.DENSITY,
-            val=constants.RHO_SEA_LEVEL_METRIC,
-            units='kg/m**3',
-        )  # not exact value but should be close enough
-        self.prob.model.set_input_defaults(
-            Aircraft.Wing.AREA, val=1370.0, units='ft**2'
-        )  # check (this is the reference wing area)
+            Dynamic.Atmosphere.DENSITY, val=constants.RHO_SEA_LEVEL_METRIC, units='kg/m**3'
+        )
+        self.prob.model.set_input_defaults(Aircraft.Wing.AREA, val=1370.0, units='ft**2')
         self.prob.model.set_input_defaults(
             Mission.Landing.LIFT_COEFFICIENT_MAX, val=3, units='unitless'
-        )  # check
+        )
 
         self.prob.setup(check=False, force_alloc_complex=True)
 
@@ -43,11 +37,10 @@ def test_case1(self):
 
         tol = 1e-5
 
+        assert_near_equal(self.prob[Mission.Landing.GROUND_DISTANCE], 6403.64963504, tol)
         assert_near_equal(
-            self.prob[Mission.Landing.GROUND_DISTANCE], 6403.64963504, tol
-        )  # not actual value
-        # not actual value
-        assert_near_equal(self.prob[Mission.Landing.INITIAL_VELOCITY], 136.22914933, tol)
+            self.prob.get_val(Mission.Landing.INITIAL_VELOCITY, units='kn'), 136.22914933, tol
+        )
 
         partial_data = self.prob.check_partials(out_stream=None, method='cs')
         assert_check_partials(partial_data, atol=1e-12, rtol=1e-12)
@@ -73,6 +66,12 @@ def test_case1(self):
             LandingCalc(),
             promotes=['*'],
         )
+        prob.model.set_input_defaults(Mission.FINAL_MASS, val=152800.0, units='lbm')
+        prob.model.set_input_defaults(
+            Dynamic.Atmosphere.DENSITY, val=constants.RHO_SEA_LEVEL_METRIC, units='kg/m**3'
+        )
+        prob.model.set_input_defaults(Aircraft.Wing.AREA, val=1370.0, units='ft**2')
+        prob.model.set_input_defaults(Mission.Landing.LIFT_COEFFICIENT_MAX, val=3, units='unitless')
         prob.setup(check=False, force_alloc_complex=True)
 
         partial_data = prob.check_partials(out_stream=None, method='cs')
@@ -91,18 +90,12 @@ def setUp(self):
             promotes=['*'],
         )
 
-        self.prob.model.set_input_defaults(
-            Mission.FINAL_MASS, val=152800.0, units='lbm'
-        )  # check (this is the design landing mass)
-        self.prob.model.set_input_defaults(
-            Mission.Landing.INITIAL_ALTITUDE, val=35, units='ft'
-        )  # confirm initial altitude should be 35 ft.
-        self.prob.model.set_input_defaults(
-            Aircraft.Wing.AREA, val=1370.0, units='ft**2'
-        )  # check (this is the reference wing area)
+        self.prob.model.set_input_defaults(Mission.FINAL_MASS, val=152800.0, units='lbm')
+        self.prob.model.set_input_defaults(Mission.Landing.INITIAL_ALTITUDE, val=35, units='ft')
+        self.prob.model.set_input_defaults(Aircraft.Wing.AREA, val=1370.0, units='ft**2')
         self.prob.model.set_input_defaults(
             Mission.Landing.LIFT_COEFFICIENT_MAX, val=3, units='unitless'
-        )  # check
+        )
 
         self.prob.setup(check=False, force_alloc_complex=True)
 
@@ -111,11 +104,10 @@ def test_case1(self):
 
         tol = 1e-5
 
+        assert_near_equal(self.prob[Mission.Landing.GROUND_DISTANCE], 6407.65299289, tol)
         assert_near_equal(
-            self.prob[Mission.Landing.GROUND_DISTANCE], 6407.65299289, tol
-        )  # not actual value
-        # not actual value
-        assert_near_equal(self.prob[Mission.Landing.INITIAL_VELOCITY], 136.22914933, tol)
+            self.prob.get_val(Mission.Landing.INITIAL_VELOCITY, units='kn'), 136.29923391, tol
+        )
 
         partial_data = self.prob.check_partials(
             out_stream=None, excludes=['*.standard_atmosphere'], method='cs'

aviary/mission/energy_state_problem_configurator.py

@@ -410,11 +410,7 @@ def add_post_mission_systems(self, aviary_group):
             )
 
         if aviary_group.post_mission_info['include_landing']:
-            if 'aircraft:wing:area' in aviary_group.aviary_inputs:
-                self._add_landing_systems(aviary_group)
-            else:
-                print('Aircraft.Wing.AREA is not given. Set include_landing = False')
-                aviary_group.post_mission_info['include_landing'] = False
+            self._add_landing_systems(aviary_group)
 
         aviary_group.add_subsystem(
             'range_constraint',
@@ -490,14 +486,9 @@ def _add_post_mission_takeoff_systems(self, aviary_group):
             )
 
     def _add_landing_systems(self, aviary_group):
-        landing_options = Landing(
-            ref_wing_area=aviary_group.aviary_inputs.get_val(Aircraft.Wing.AREA, units='ft**2'),
-            Cl_max_ldg=aviary_group.aviary_inputs.get_val(
-                Mission.Landing.LIFT_COEFFICIENT_MAX
-            ),  # no units
-        )
+        landing_options = Landing()
 
-        landing = landing_options.build_phase(False)
+        landing = landing_options.build_phase(use_detailed=False)
 
         aviary_group.add_subsystem(
             'landing',

aviary/utils/test/data/converter_test_BWB_detailed_FLOPS.csv

@@ -90,7 +90,6 @@ aircraft:wing:thickness_to_chord_distribution,-1.0,0.15,0.1132,0.0928,0.0822,0.0
 aircraft:wing:ultimate_load_factor,3.75,unitless
 aircraft:wing:var_sweep_mass_penalty,0,unitless
 mission:constraints:max_mach,0.85,unitless
-mission:landing:initial_velocity,140,ft/s
 mission:landing:lift_coefficient_max,3.0,unitless
 mission:takeoff:braking_friction_coefficient,0.3,unitless
 mission:takeoff:rolling_friction_coefficient,0.025,unitless
@@ -104,6 +103,7 @@ AERIN.FLTO,11000
 AERIN.ITPAER,2
 AERIN.MYAERO,0
 AERIN.THROFF,0.25
+AERIN.VAPPR,140
 AERIN.XLLAM,0
 CONFIN.CH,39000
 CONFIN.GW,874099

aviary/utils/test/data/converter_test_BWB_simple_FLOPS.csv

@@ -89,7 +89,6 @@ aircraft:wing:thickness_to_chord,0.11,unitless
 aircraft:wing:ultimate_load_factor,3.75,unitless
 aircraft:wing:var_sweep_mass_penalty,0,unitless
 mission:constraints:max_mach,0.85,unitless
-mission:landing:initial_velocity,140,ft/s
 mission:landing:lift_coefficient_max,3.0,unitless
 mission:takeoff:braking_friction_coefficient,0.3,unitless
 mission:takeoff:rolling_friction_coefficient,0.025,unitless
@@ -103,6 +102,7 @@ AERIN.FLTO,11000
 AERIN.ITPAER,2
 AERIN.MYAERO,0
 AERIN.THROFF,0.25
+AERIN.VAPPR,140
 AERIN.XLLAM,0
 CONFIN.CH,39000
 CONFIN.GW,874099