Merge pull request #87 from fast-aircraft-design/increased_MDA_robustness

Increased mda robustness by allowing k_sfc extrapolation and addition of warning for negative chords due to unfeasible wing geometry

Author: enricostragiotti

src/fastoad_cs25/models/geometry/geom_components/wing/components/compute_l1_l4.py

@@ -16,8 +16,12 @@
 
 import numpy as np
 import openmdao.api as om
+from fastoad.api import ValidityDomainChecker
 
 
+@ValidityDomainChecker(
+    {"data:geometry:wing:root:virtual_chord": (0.0, None)},
+)
 class ComputeL1AndL4Wing(om.ExplicitComponent):
     # TODO: Document equations. Cite sources
     """Wing chords (l1 and l4) estimation"""

src/fastoad_cs25/models/geometry/geom_components/wing/components/tests/test_wing_geom_comps.py

@@ -84,6 +84,29 @@ def test_geometry_wing_l1_l4():
     assert wing_l4 == pytest.approx(1.882, abs=1e-3)
 
 
+def test_activation_warning_for_negative_l1(caplog):
+    """Test if a warning is generated when an unfeasible wing geometry is input and results
+    in a negative chord value. Unfeasible geometries concerned especially wings with high aspect
+    ratio, far lateral kink, and high sweep, low inner-kink trailing sweep."""
+
+    input_vars = om.IndepVarComp()
+    input_vars.add_output("data:geometry:wing:area", 50, units="m**2")
+    input_vars.add_output("data:geometry:wing:sweep_25", 27.0, units="deg")
+    input_vars.add_output("data:geometry:wing:virtual_taper_ratio", 0.9, units=None)
+    input_vars.add_output("data:geometry:wing:kink:y", 12, units="m")
+    input_vars.add_output("data:geometry:wing:root:y", 1.96, units="m")
+    input_vars.add_output("data:geometry:wing:tip:y", 15.8015, units="m")
+
+    problem = run_system(ComputeL1AndL4Wing(), input_vars)
+    wing_l1 = problem["data:geometry:wing:root:virtual_chord"]
+
+    # Check for the core part of the warning message
+    expected_core = (
+        f'"data:geometry:wing:root:virtual_chord" out of bound: value [{wing_l1[0]:.8f}] m'
+    )
+    assert expected_core in caplog.text, f"Expected warning not found in logs. Logs: {caplog.text}"
+
+
 def test_geometry_wing_l2_l3():
     """Tests computation of the wing chords (l2 and l3)"""
 

src/fastoad_cs25/models/propulsion/fuel_propulsion/rubber_engine/rubber_engine.py

@@ -129,6 +129,8 @@ def compute_flight_points(self, flight_points: Union[FlightPoint, pd.DataFrame])
         k_sfc_alt = interp1d(
             [-1000.0, 0.0, 13106.4, 20000.0],
             np.hstack((self.k_sfc_sl, self.k_sfc_sl, self.k_sfc_cr, self.k_sfc_cr)),
+            bounds_error=False,
+            fill_value=(self.k_sfc_sl, self.k_sfc_cr),
         )
         k_sfc = k_sfc_alt(flight_points.altitude)
 

src/fastoad_cs25/models/propulsion/fuel_propulsion/rubber_engine/tests/test_rubber_engine.py

@@ -43,6 +43,18 @@ def test_compute_flight_points():
     np.testing.assert_allclose(flight_point.thrust_rate, 0.5, rtol=1e-4)
     np.testing.assert_allclose(flight_point.sfc, 1.3496e-5, rtol=1e-4)
 
+    flight_point = FlightPoint(
+        mach=0, altitude=-3000, engine_setting=EngineSetting.TAKEOFF, thrust_rate=0.8
+    )  # with altitude below boundaries of k_sfc interpolation
+    engine.compute_flight_points(flight_point)
+    np.testing.assert_allclose(flight_point.sfc, 1.02479e-05, rtol=1e-4)
+
+    flight_point = FlightPoint(
+        mach=0.8, altitude=30000, engine_setting=EngineSetting.CRUISE.value, thrust_rate=0.7
+    )  # with altitude above boundaries of k_sfc interpolation
+    engine.compute_flight_points(flight_point)
+    np.testing.assert_allclose(flight_point.sfc, 1.42638e-05, rtol=1e-4)
+
     # Test full arrays
     # 2D arrays are used, where first line is for thrust rates, and second line
     # is for thrust values.