[Hotfix Main]: Fix bug that dimensionalization used wrong velocity scale (#1362)

* Fix bug that dimensionalization used wrong velocity scale (#1361)

* Fix bug that dimensionalization used wrong velocity scale

* Fix unit test

* Fix formatting

* Fixed unit test

---------

Co-authored-by: Ben <106089368+benflexcompute@users.noreply.github.com>
Co-authored-by: BenYuan <ben@flexcompute.com>

Author: github-actions[bot]

flow360/component/simulation/conversion.py

@@ -362,15 +362,45 @@ def get_base_thermal_conductivity():
     return flow360_conversion_unit_system.conversion_system
 
 
-def get_flow360_unit_system_liquid(params) -> u.UnitSystem:
+def get_flow360_unit_system_liquid(params, to_flow360_unit: bool = False) -> u.UnitSystem:
     """
-    Returns the flow360 unit system when liquid operating condition is used
+    Returns the flow360 unit system when liquid operating condition is used.
+
+    Parameters
+    ----------
+    params : SimulationParams
+        The parameters needed for unit conversion.
+    to_flow360_unit : bool, optional
+        If True, return the flow360 unit system.
+
+    Returns
+    -------
+    u.UnitSystem
+        The flow360 unit system.
+
+    ##-- When to_flow360_unit is True,
+    ##-- time unit should be changed such that it takes into consideration
+    ##-- the fact that solver output already multiplied by "velocityScale"
     """
+
+    if to_flow360_unit:
+        base_velocity = params.base_velocity
+    else:
+        # For dimensionalization of Flow360 output
+        # The solver output is already re-normalized by `reference velocity` due to "velocityScale"
+        # So we need to find the `reference velocity`.
+        # `reference_velocity_magnitude` takes precedence, consistent with how "velocityScale" is computed.
+        if params.operating_condition.reference_velocity_magnitude is not None:
+            base_velocity = (params.operating_condition.reference_velocity_magnitude).to("m/s")
+        else:
+            base_velocity = params.base_velocity.to("m/s") * LIQUID_IMAGINARY_FREESTREAM_MACH
+
+    time_unit = params.base_length / base_velocity
     return u.UnitSystem(
         name="flow360_liquid",
         length_unit=params.base_length,
         mass_unit=params.base_mass,
-        time_unit=params.base_time / LIQUID_IMAGINARY_FREESTREAM_MACH,
+        time_unit=time_unit,
         temperature_unit=params.base_temperature,
     )
 

tests/simulation/translator/ref/Flow360_liquid_rotation_dd.json

@@ -89,6 +89,10 @@
         }
     },
     "userDefinedFields": [
+        {
+            "expression": "double ___velocity[3];___velocity[0] = primitiveVars[1] * velocityScale;___velocity[1] = primitiveVars[2] * velocityScale;___velocity[2] = primitiveVars[3] * velocityScale;velocity_SI[0] = (___velocity[0] * 10.0); velocity_SI[1] = (___velocity[1] * 10.0); velocity_SI[2] = (___velocity[2] * 10.0);",
+            "name": "velocity_SI"
+        },
         {
             "expression": "double velocity[3];velocity[0] = primitiveVars[1];velocity[1] = primitiveVars[2];velocity[2] = primitiveVars[3];velocity_magnitude = magnitude(velocity) * velocityScale;",
             "name": "velocity_magnitude",
@@ -99,6 +103,17 @@
     "outputRescale": {
         "velocityScale": 20.0
     },
+    "volumeOutput": {
+        "animationFrequency": -1,
+        "animationFrequencyOffset": 0,
+        "animationFrequencyTimeAverage": -1,
+        "animationFrequencyTimeAverageOffset": 0,
+        "outputFields": [
+            "velocity_SI"
+        ],
+        "outputFormat": "paraview",
+        "startAverageIntegrationStep": -1
+    },
     "volumeZones": {
         "zone_zone_1": {
             "referenceFrame": {

tests/simulation/translator/ref/Flow360_liquid_rotation_dd_with_ref_vel.json

@@ -0,0 +1,137 @@
+{
+    "freestream": {
+        "alphaAngle": 5.0,
+        "betaAngle": 2.0,
+        "Mach": 0.05,
+        "Temperature": -1,
+        "muRef": 4.554545454545455e-09,
+        "MachRef": 0.1
+    },
+    "timeStepping": {
+        "CFL": {
+            "type": "adaptive",
+            "min": 0.1,
+            "max": 1000000.0,
+            "maxRelativeChange": 50.0,
+            "convergenceLimitingFactor": 1.0
+        },
+        "physicalSteps": 100,
+        "orderOfAccuracy": 2,
+        "maxPseudoSteps": 20,
+        "timeStepSize": 80.0
+    },
+    "navierStokesSolver": {
+        "absoluteTolerance": 1e-10,
+        "relativeTolerance": 0.0,
+        "orderOfAccuracy": 2,
+        "linearSolver": {
+            "maxIterations": 30
+        },
+        "CFLMultiplier": 1.0,
+        "kappaMUSCL": -1.0,
+        "numericalDissipationFactor": 1.0,
+        "limitVelocity": false,
+        "limitPressureDensity": false,
+        "lowMachPreconditioner": true,
+        "updateJacobianFrequency": 4,
+        "maxForceJacUpdatePhysicalSteps": 0,
+        "lowMachPreconditionerThreshold": 0.05,
+        "modelType": "Compressible",
+        "equationEvalFrequency": 1
+    },
+    "turbulenceModelSolver": {
+        "absoluteTolerance": 1e-08,
+        "relativeTolerance": 0.0,
+        "orderOfAccuracy": 2,
+        "linearSolver": {
+            "maxIterations": 20
+        },
+        "CFLMultiplier": 2.0,
+        "reconstructionGradientLimiter": 0.5,
+        "quadraticConstitutiveRelation": false,
+        "updateJacobianFrequency": 4,
+        "maxForceJacUpdatePhysicalSteps": 0,
+        "rotationCorrection": false,
+        "equationEvalFrequency": 4,
+        "modelType": "SpalartAllmaras",
+        "modelConstants": {
+            "C_DES": 0.72,
+            "C_d": 8.0,
+            "C_cb1": 0.1355,
+            "C_cb2": 0.622,
+            "C_sigma": 0.6666666666666666,
+            "C_v1": 7.1,
+            "C_vonKarman": 0.41,
+            "C_w2": 0.3,
+            "C_t3": 1.2,
+            "C_t4": 0.5,
+            "C_min_rd": 10.0
+        },
+        "DDES": false,
+        "ZDES": false,
+        "gridSizeForLES": "maxEdgeLength"
+    },
+    "initialCondition": {
+        "type": "initialCondition",
+        "rho": "rho",
+        "u": "u",
+        "v": "v",
+        "w": "w",
+        "p": "p"
+    },
+    "boundaries": {
+        "fluid/body": {
+            "type": "NoSlipWall",
+            "heatFlux": 0.0,
+            "roughnessHeight": 0.0
+        },
+        "fluid/farfield": {
+            "type": "Freestream"
+        }
+    },
+    "userDefinedFields": [
+        {
+            "expression": "double ___velocity[3];___velocity[0] = primitiveVars[1] * velocityScale;___velocity[1] = primitiveVars[2] * velocityScale;___velocity[2] = primitiveVars[3] * velocityScale;velocity_SI[0] = (___velocity[0] * 20.0); velocity_SI[1] = (___velocity[1] * 20.0); velocity_SI[2] = (___velocity[2] * 20.0);",
+            "name": "velocity_SI"
+        },
+        {
+            "expression": "double velocity[3];velocity[0] = primitiveVars[1];velocity[1] = primitiveVars[2];velocity[2] = primitiveVars[3];velocity_magnitude = magnitude(velocity) * velocityScale;",
+            "name": "velocity_magnitude",
+            "from_user_variables": false
+        }
+    ],
+    "usingLiquidAsMaterial": true,
+    "outputRescale": {
+        "velocityScale": 10.0
+    },
+    "volumeOutput": {
+        "animationFrequency": -1,
+        "animationFrequencyOffset": 0,
+        "animationFrequencyTimeAverage": -1,
+        "animationFrequencyTimeAverageOffset": 0,
+        "outputFields": [
+            "velocity_SI"
+        ],
+        "outputFormat": "paraview",
+        "startAverageIntegrationStep": -1
+    },
+    "volumeZones": {
+        "zone_zone_1": {
+            "referenceFrame": {
+                "axisOfRotation": [
+                    0.6,
+                    0.8,
+                    0.0
+                ],
+                "centerOfRotation": [
+                    0.01,
+                    0.01,
+                    0.01
+                ],
+                "thetaRadians": "-180/pi * atan(2 * 3.00 * 20.00 * 2.00/180*pi * cos(2.00/180*pi * sin(0.05877271 * (0.005 * t))) * cos(0.05877271 * (0.005 * t)) / 200.00) + 2 * 2.00 * sin(0.05877271 * (0.005 * t)) - 2.00 * sin(0.05877271 * (0.005 * t))"
+            },
+            "modelType": "FluidDynamics",
+            "isRotatingReferenceFrame": false
+        }
+    }
+}

tests/simulation/translator/test_output_translation.py

@@ -1360,7 +1360,7 @@ def test_dimensioned_output_fields_translation(vel_in_km_per_hr):
             {"name": "my_field", "expression": "1+1", "from_user_variables": False},
             {
                 "name": "pressure_pa",
-                "expression": "double pressure_;double gamma = 1.4;pressure_ = (usingLiquidAsMaterial) ? (primitiveVars[4] - 1.0 / gamma) * (velocityScale * velocityScale) : primitiveVars[4];pressure_pa = pressure_ * 2500000.0;",
+                "expression": "double pressure_;double gamma = 1.4;pressure_ = (usingLiquidAsMaterial) ? (primitiveVars[4] - 1.0 / gamma) * (velocityScale * velocityScale) : primitiveVars[4];pressure_pa = pressure_ * 10000000.0;",
                 "from_user_variables": False,
             },
             {
@@ -1370,11 +1370,11 @@ def test_dimensioned_output_fields_translation(vel_in_km_per_hr):
             },
             {
                 "name": "velocity_in_km_per_hr",
-                "expression": "double ___velocity[3];___velocity[0] = primitiveVars[1] * velocityScale;___velocity[1] = primitiveVars[2] * velocityScale;___velocity[2] = primitiveVars[3] * velocityScale;velocity_in_km_per_hr[0] = (___velocity[0] * 180.0); velocity_in_km_per_hr[1] = (___velocity[1] * 180.0); velocity_in_km_per_hr[2] = (___velocity[2] * 180.0);",
+                "expression": "double ___velocity[3];___velocity[0] = primitiveVars[1] * velocityScale;___velocity[1] = primitiveVars[2] * velocityScale;___velocity[2] = primitiveVars[3] * velocityScale;velocity_in_km_per_hr[0] = (___velocity[0] * 360.0); velocity_in_km_per_hr[1] = (___velocity[1] * 360.0); velocity_in_km_per_hr[2] = (___velocity[2] * 360.0);",
             },
             {
                 "name": "velocity_m_per_s",
-                "expression": "double velocity[3];velocity[0] = primitiveVars[1] * velocityScale;velocity[1] = primitiveVars[2] * velocityScale;velocity[2] = primitiveVars[3] * velocityScale;velocity_m_per_s[0] = velocity[0] * 50.0;velocity_m_per_s[1] = velocity[1] * 50.0;velocity_m_per_s[2] = velocity[2] * 50.0;",
+                "expression": "double velocity[3];velocity[0] = primitiveVars[1] * velocityScale;velocity[1] = primitiveVars[2] * velocityScale;velocity[2] = primitiveVars[3] * velocityScale;velocity_m_per_s[0] = velocity[0] * 100.0;velocity_m_per_s[1] = velocity[1] * 100.0;velocity_m_per_s[2] = velocity[2] * 100.0;",
                 "from_user_variables": False,
             },
             {
@@ -1384,22 +1384,22 @@ def test_dimensioned_output_fields_translation(vel_in_km_per_hr):
             },
             {
                 "name": "velocity_magnitude_m_per_s",
-                "expression": "double velocity_magnitude;double velocity[3];velocity[0] = primitiveVars[1];velocity[1] = primitiveVars[2];velocity[2] = primitiveVars[3];velocity_magnitude = magnitude(velocity) * velocityScale;velocity_magnitude_m_per_s = velocity_magnitude * 50.0;",
+                "expression": "double velocity_magnitude;double velocity[3];velocity[0] = primitiveVars[1];velocity[1] = primitiveVars[2];velocity[2] = primitiveVars[3];velocity_magnitude = magnitude(velocity) * velocityScale;velocity_magnitude_m_per_s = velocity_magnitude * 100.0;",
                 "from_user_variables": False,
             },
             {
                 "name": "velocity_x_m_per_s",
-                "expression": "double velocity_x;velocity_x = primitiveVars[1] * velocityScale;velocity_x_m_per_s = velocity_x * 50.0;",
+                "expression": "double velocity_x;velocity_x = primitiveVars[1] * velocityScale;velocity_x_m_per_s = velocity_x * 100.0;",
                 "from_user_variables": False,
             },
             {
                 "name": "velocity_y_m_per_s",
-                "expression": "double velocity_y;velocity_y = primitiveVars[2] * velocityScale;velocity_y_m_per_s = velocity_y * 50.0;",
+                "expression": "double velocity_y;velocity_y = primitiveVars[2] * velocityScale;velocity_y_m_per_s = velocity_y * 100.0;",
                 "from_user_variables": False,
             },
             {
                 "name": "velocity_z_m_per_s",
-                "expression": "double velocity_z;velocity_z = primitiveVars[3] * velocityScale;velocity_z_m_per_s = velocity_z * 50.0;",
+                "expression": "double velocity_z;velocity_z = primitiveVars[3] * velocityScale;velocity_z_m_per_s = velocity_z * 100.0;",
                 "from_user_variables": False,
             },
             {
@@ -1414,7 +1414,7 @@ def test_dimensioned_output_fields_translation(vel_in_km_per_hr):
             },
             {
                 "name": "wall_shear_stress_magnitude_pa",
-                "expression": "double wall_shear_stress_magnitude;wall_shear_stress_magnitude = magnitude(wallShearStress) * (velocityScale * velocityScale);wall_shear_stress_magnitude_pa = wall_shear_stress_magnitude * 2500000.0;",
+                "expression": "double wall_shear_stress_magnitude;wall_shear_stress_magnitude = magnitude(wallShearStress) * (velocityScale * velocityScale);wall_shear_stress_magnitude_pa = wall_shear_stress_magnitude * 10000000.0;",
                 "from_user_variables": False,
             },
         ]

tests/simulation/translator/test_solver_translator.py

@@ -68,6 +68,7 @@
 from flow360.component.simulation.user_code.core.types import UserVariable
 from flow360.component.simulation.user_code.functions import math
 from flow360.component.simulation.user_code.variables import solution
+from flow360.component.simulation.utils import model_attribute_unlock
 from tests.simulation.translator.utils.actuator_disk_param_generator import (
     actuator_disk_create_param,
 )
@@ -671,12 +672,29 @@ def test_liquid_simulation_translation():
                 ),
             ],
             time_stepping=Unsteady(steps=100, step_size=0.4),
+            outputs=[
+                VolumeOutput(
+                    name="output",
+                    output_fields=[solution.velocity],
+                )
+            ],
         )
         # Derivation:
         # Solver speed of sound = 10m/s / 0.05 = 200m/s
         # Flow360 time to seconds = 1m/(200m/s) = 0.005 s
         # t_seconds = (0.005 s * t)
-    translate_and_compare(param, mesh_unit=1 * u.m, ref_json_file="Flow360_liquid_rotation_dd.json")
+    translate_and_compare(
+        param, mesh_unit=1 * u.m, ref_json_file="Flow360_liquid_rotation_dd.json", debug=True
+    )
+
+    with model_attribute_unlock(param.operating_condition, "reference_velocity_magnitude"):
+        param.operating_condition.reference_velocity_magnitude = 20 * u.m / u.s
+    translate_and_compare(
+        param,
+        mesh_unit=1 * u.m,
+        ref_json_file="Flow360_liquid_rotation_dd_with_ref_vel.json",
+        debug=True,
+    )
 
 
 def test_param_with_user_variables():