Fixed a bug where the area as well as the ref Mach is not computed correctly (#1592)

* Fixed a bug where the area as well as the ref Mach is not computed correclty

* Added support for PM header that does not start with zone_

Author: benflexcompute

flow360/component/results/results_utils.py

@@ -15,6 +15,7 @@
 )
 from flow360.component.simulation.models.volume_models import BETDisk
 from flow360.component.simulation.simulation_params import SimulationParams
+from flow360.component.simulation.user_code.core.types import Expression
 from flow360.exceptions import Flow360ValueError
 from flow360.log import log
 
@@ -75,21 +76,28 @@ def _vector_to_np3(vec):
         raise Flow360ValueError(f"Invalid vector: {vec}") from exc
 
 
-def _get_reference_geometry(params: SimulationParams):
+def _get_reference_geometry_in_flow360_unit(params: SimulationParams):
     # pylint:disable=import-outside-toplevel, no-member, protected-access
     from flow360.component.simulation.primitives import ReferenceGeometry
 
-    # Fill defaults using preprocessed params
     reference_geometry_filled = ReferenceGeometry.fill_defaults(params.reference_geometry, params)
 
-    reference_geometry_filled_flow360: ReferenceGeometry = reference_geometry_filled.preprocess(
-        params=params
-    )
+    evaluated_area = None
+    if isinstance(reference_geometry_filled.area, Expression):
+        evaluated_area = reference_geometry_filled.area.evaluate(
+            raise_on_non_evaluable=True, force_evaluate=True
+        )
+    else:
+        evaluated_area = reference_geometry_filled.area
+    # Fill defaults using preprocessed params
+
     # Extract dimensionless area (in Flow360 units)
-    area_flow360 = float(reference_geometry_filled_flow360.area.value)
+    area_flow360 = float(evaluated_area.in_base(params.flow360_unit_system).value)
 
     # Extract dimensionless moment_length
-    moment_length_flow360 = reference_geometry_filled_flow360.moment_length
+    moment_length_flow360 = reference_geometry_filled.moment_length.in_base(
+        params.flow360_unit_system
+    )
 
     # Convert to numpy array properly - handle both arrays and scalars
     try:
@@ -109,7 +117,7 @@ def _get_reference_geometry(params: SimulationParams):
         moment_length_vec_flow360 = np.array([scalar_val, scalar_val, scalar_val], dtype=float)
 
     # Extract dimensionless moment_center
-    moment_center = reference_geometry_filled_flow360.moment_center
+    moment_center = reference_geometry_filled.moment_center.in_base(params.flow360_unit_system)
     moment_center_flow360 = np.array(
         [moment_center[0], moment_center[1], moment_center[2]],
         dtype=float,
@@ -154,21 +162,19 @@ def _get_lift_drag_direction(params: SimulationParams):
 
 def _get_dynamic_pressure_in_flow360_unit(params: SimulationParams):
     # pylint:disable=protected-access
-    oc = params.operating_condition
-    using_liquid_op = oc.type_name == "LiquidOperatingCondition"
 
-    if using_liquid_op:
-        v_ref = params._liquid_reference_velocity
-    else:
-        v_ref = params.base_velocity
+    v_ref = params.reference_velocity
 
     Mach_ref = params.convert_unit(value=v_ref, target_system="flow360").value
     return 0.5 * Mach_ref * Mach_ref
 
 
 def _build_coeff_env(params) -> Dict[str, Any]:
+    """
+    Get data for computing aerodynamic coefficients in flow360 unit.
+    """
     # pylint:disable=protected-access
-    area, moment_length_vec, moment_center_global = _get_reference_geometry(params)
+    area, moment_length_vec, moment_center_global = _get_reference_geometry_in_flow360_unit(params)
     dynamic_pressure = _get_dynamic_pressure_in_flow360_unit(params)
     lift_dir, drag_dir = _get_lift_drag_direction(params)
     return {
@@ -341,14 +347,16 @@ def _copy_time_columns(src: Dict[str, list]) -> Dict[str, list]:
 
     @staticmethod
     def _iter_zones(values: Dict[str, list]):
-        zone_names = np.unique(
-            [
-                v.split("_")[0] + "_" + v.split("_")[1]
-                for v in values.keys()
-                if v.startswith("zone_")
-            ]
-        )
-        yield from zone_names
+        # Support both default "zone_<idx>_<...>" and arbitrary GenericVolume-style names
+        # such as "blk-2_Force_x" by extracting the prefix before Force/Moment components.
+        pattern = re.compile(r"^(?P<zone>.+?)_(?:Force|Moment)_[xyz]$")
+        zone_set = set()
+        for key in values.keys():
+            match = pattern.match(key)
+            if match:
+                zone_set.add(match.group("zone"))
+        # Keep deterministic order similar to np.unique behavior
+        yield from sorted(zone_set)
 
     @staticmethod
     def _init_zone_output(out: Dict[str, list], zone_name: str) -> Dict[str, str]:

flow360/component/simulation/conversion.py

@@ -369,7 +369,7 @@ def get_flow360_unit_system_liquid(params, to_flow360_unit: bool = False) -> u.U
     Parameters
     ----------
     params : SimulationParams
-        The parameters needed for unit conversion.
+        The parameters needed for unit conversion that uses liquid operating condition.
     to_flow360_unit : bool, optional
         Whether we want user input to be converted to flow360 unit system.
         The reverse path requires different conversion logic (from solver output to non-flow360 unit system)
@@ -388,7 +388,7 @@ def get_flow360_unit_system_liquid(params, to_flow360_unit: bool = False) -> u.U
     if to_flow360_unit:
         base_velocity = params.base_velocity
     else:
-        base_velocity = params._liquid_reference_velocity  # pylint:disable=protected-access
+        base_velocity = params.reference_velocity  # pylint:disable=protected-access
 
     time_unit = params.base_length / base_velocity
     return u.UnitSystem(

flow360/component/simulation/simulation_params.py

@@ -648,9 +648,9 @@ def base_velocity(self) -> VelocityType:
         return self.operating_condition.thermal_state.speed_of_sound.to("m/s")
 
     @property
-    def _liquid_reference_velocity(self) -> VelocityType:
+    def reference_velocity(self) -> VelocityType:
         """
-        This function returns the reference velocity for liquid operating condition.
+        This function returns the **reference velocity**.
         Note that the reference velocity is **NOT** the non-dimensionalization velocity scale
 
         For dimensionalization of Flow360 output (converting FROM flow360 unit)
@@ -661,8 +661,10 @@ def _liquid_reference_velocity(self) -> VelocityType:
         # pylint:disable=no-member
         if self.operating_condition.reference_velocity_magnitude is not None:
             reference_velocity = (self.operating_condition.reference_velocity_magnitude).to("m/s")
-        else:
+        elif self.operating_condition.type_name == "LiquidOperatingCondition":
             reference_velocity = self.base_velocity.to("m/s") * LIQUID_IMAGINARY_FREESTREAM_MACH
+        else:
+            reference_velocity = self.operating_condition.velocity_magnitude.to("m/s")
         return reference_velocity
 
     @property

tests/simulation/data/real_case_coefficients/results/reference_coefficients.json

@@ -3,106 +3,106 @@
     "Disk0": {
       "CFx": 0.0,
       "CFy": 0.0,
-      "CFz": 4.22968413996175e-08,
-      "CMx": -1.8127217742693215e-07,
-      "CMy": -8.157247984211948e-08,
-      "CMz": 3.403336579930425e-09,
-      "CD": 1.0947228101901768e-08,
-      "CL": 4.0855611478343206e-08
+      "CFz": 9.995866680607329e-11,
+      "CMx": -4.2839428631174267e-10,
+      "CMy": -1.927774288402842e-10,
+      "CMz": 8.042987985983815e-14,
+      "CL": 9.655265782941001e-11,
+      "CD": 2.5871206692468927e-11
     },
     "Disk1": {
       "CFx": 0.0,
       "CFy": 0.0,
-      "CFz": 4.22968413996175e-08,
-      "CMx": 8.00618783635617e-08,
-      "CMy": -8.157247984211948e-08,
-      "CMz": 3.403336579930425e-09,
-      "CD": 1.0947228101901768e-08,
-      "CL": 4.0855611478343206e-08
+      "CFz": 9.995866680607329e-11,
+      "CMx": 1.8920747645435302e-10,
+      "CMy": -1.927774288402842e-10,
+      "CMz": 8.042987985983815e-14,
+      "CL": 9.655265782941001e-11,
+      "CD": 2.5871206692468927e-11
     },
     "Disk2": {
       "CFx": 0.0,
       "CFy": 0.0,
-      "CFz": 4.22968413996175e-08,
-      "CMx": -8.00618783635617e-08,
-      "CMy": -8.157247984211948e-08,
-      "CMz": 3.4033365799304168e-09,
-      "CD": 1.0947228101901768e-08,
-      "CL": 4.0855611478343206e-08
+      "CFz": 9.995866680607329e-11,
+      "CMx": -1.8920747645435302e-10,
+      "CMy": -1.927774288402842e-10,
+      "CMz": 8.042987985983795e-14,
+      "CL": 9.655265782941001e-11,
+      "CD": 2.5871206692468927e-11
     },
     "Disk3": {
       "CFx": 0.0,
       "CFy": 0.0,
-      "CFz": 4.22968413996175e-08,
-      "CMx": 1.8127217742693215e-07,
-      "CMy": -8.157247984211948e-08,
-      "CMz": 3.403336579930425e-09,
-      "CD": 1.0947228101901768e-08,
-      "CL": 4.0855611478343206e-08
+      "CFz": 9.995866680607329e-11,
+      "CMx": 4.2839428631174267e-10,
+      "CMy": -1.927774288402842e-10,
+      "CMz": 8.042987985983815e-14,
+      "CL": 9.655265782941001e-11,
+      "CD": 2.5871206692468927e-11
     }
   },
   "BETDisk": {
     "Disk0": {
-      "CFx": -0.0013623562270260357,
-      "CFy": 3.408410091892857e-05,
-      "CFz": 0.0007882827772506428,
-      "CMx": -0.002831401005472502,
-      "CMy": 0.0005588765009247424,
-      "CMz": -0.005219742604944044,
-      "CD": -0.0011119124686114067,
-      "CL": 0.0011140264307336204
+      "CFx": -3.219609494757832e-06,
+      "CFy": 8.054978041860516e-08,
+      "CFz": 1.8629215060223306e-06,
+      "CMx": -8.003490657116154e-06,
+      "CMy": 1.284310828124118e-06,
+      "CMz": -1.389477191280391e-05,
+      "CL": 2.632740250052527e-06,
+      "CD": -2.6277443962624396e-06
     },
     "Disk1": {
-      "CFx": -0.0013625962301961904,
-      "CFy": 3.430884768042857e-05,
-      "CFz": 0.0007882460542094166,
-      "CMx": 0.002040468650507854,
-      "CMy": 0.0006176229491711534,
-      "CMz": 0.0031976789226962144,
-      "CD": -0.001112153798494314,
-      "CL": 0.001114053076391001
+      "CFx": -3.2201766859741037e-06,
+      "CFy": 8.108091669037237e-08,
+      "CFz": 1.8628347197252796e-06,
+      "CMx": 3.5097996437133253e-06,
+      "CMy": 1.4219783685337042e-06,
+      "CMz": 5.998145947634071e-06,
+      "CL": 2.6328032208158226e-06,
+      "CD": -2.6283147228532113e-06
     },
     "Disk2": {
-      "CFx": -0.001362673711029595,
-      "CFy": -3.4279632118202374e-05,
-      "CFz": 0.0007882642235870595,
-      "CMx": -0.002040542978745176,
-      "CMy": 0.0006176049504929208,
-      "CMz": -0.003197903001473004,
-      "CD": -0.00111222393665137,
-      "CL": 0.0011140906801774294
+      "CFx": -3.220359793756006e-06,
+      "CFy": -8.101187255957007e-08,
+      "CFz": 1.862877658788949e-06,
+      "CMx": -3.509906765297771e-06,
+      "CMy": 1.4219711165652415e-06,
+      "CMz": -5.998589581039346e-06,
+      "CL": 2.632892088547641e-06,
+      "CD": -2.6284804779412884e-06
     },
     "Disk3": {
-      "CFx": -0.0013623581648587975,
-      "CFy": -3.403408826757143e-05,
-      "CFz": 0.0007883305725700714,
-      "CMx": 0.0028315934600057083,
-      "CMy": 0.0005589131586812199,
-      "CMz": 0.005219704135600682,
-      "CD": -0.0011119019700751836,
-      "CL": 0.001114073099015057
+      "CFx": -3.219614074371178e-06,
+      "CFy": -8.043158724418193e-08,
+      "CFz": 1.8630344590526649e-06,
+      "CMx": 8.003926808607675e-06,
+      "CMy": 1.2844656026937008e-06,
+      "CMz": 1.389462745437122e-05,
+      "CL": 2.632850539592837e-06,
+      "CD": -2.6277195854337923e-06
     }
   },
   "PorousMedium": {
     "zone_0": {
-      "CFx": 2.0891243317035,
+      "CFx": 0.004937155496228122,
       "CFy": 0.0,
       "CFz": 0.0,
       "CMx": 0.0,
-      "CMy": 0.7578755447937788,
-      "CMz": -6.609346148473639e-05,
-      "CD": 2.017939146321301,
-      "CL": -0.5407051646319416
+      "CMy": 1.7910611420548698e-05,
+      "CMz": -1.561963985015805e-09,
+      "CL": -0.0012778298710564243,
+      "CD": 0.004768926002211764
     },
     "zone_1": {
-      "CFx": 18.46648378443988,
+      "CFx": 0.04364120436911098,
       "CFy": 0.0,
       "CFz": 0.0,
       "CMx": 0.0,
-      "CMy": 6.600353840412458,
-      "CMz": -0.0023132093922757484,
-      "CD": 17.837253608138774,
-      "CL": -4.779477699489913
+      "CMy": 0.0001559838863858854,
+      "CMz": -5.4667279930094694e-08,
+      "CL": -0.01129517484193726,
+      "CD": 0.04215416639048362
     }
   }
 }

tests/simulation/data/real_case_coefficients/results/simulation_params.json

@@ -5,6 +5,7 @@
 
 import flow360 as fl
 from flow360.component.results.case_results import BETForcesResultCSVModel
+from flow360.component.results.results_utils import _build_coeff_env
 from flow360.component.simulation.framework.param_utils import AssetCache
 from flow360.component.simulation.models.volume_models import BETDisk
 from flow360.component.simulation.services import ValidationCalledBy, validate_model
@@ -172,12 +173,22 @@ def test_bet_disk_real_case_coefficients():
         params_json = f.read()
 
     params_as_dict = json.loads(params_json)
-    params, errors, warnings = validate_model(
+    params, errors, _ = validate_model(
         params_as_dict=params_as_dict,
         validated_by=ValidationCalledBy.LOCAL,
         root_item_type=None,
     )
 
+    mach_ref = params.operating_condition.mach
+
+    coeff_env = _build_coeff_env(params)
+    assert coeff_env["dynamic_pressure"] == 0.5 * mach_ref * mach_ref
+    assert coeff_env["area"] == (params.reference_geometry.area / (1.0 * fl.u.cm**2)).value
+    assert np.allclose(coeff_env["moment_length_vec"], [140, 140, 140])
+    assert np.allclose(coeff_env["moment_center_global"], [0, 0, 0])
+    assert np.allclose(coeff_env["lift_dir"], [-0.25881905, 0.0, 0.96592583])
+    assert np.allclose(coeff_env["drag_dir"], [0.96592583, -0.0, 0.25881905])
+
     assert errors is None, f"Validation errors: {errors}"
     assert params is not None