mass instead of volume as base attribute (incl. introduction of physi…

…cs.particle_shape_and_density) (#1147)

Co-authored-by: Oleksii Bulenok <[email protected]>
Co-authored-by: Agnieszka Makulska <[email protected]>
Co-authored-by: derlk <[email protected]>

.gitignore

@@ -134,4 +134,7 @@ dmypy.json
 .code-workspace
 
 # Mac stuff
-**.DS_Store
+**.DS_Store
+
+#Jetbrains
+.idea/

PySDM/attributes/impl/mapper.py

@@ -24,6 +24,7 @@
     Temperature,
     TerminalVelocity,
     Volume,
+    WaterMass,
     WetToCriticalVolumeRatio,
 )
 from PySDM.attributes.physics.critical_supersaturation import CriticalSupersaturation
@@ -100,6 +101,7 @@
     "critical supersaturation": lambda _, __: CriticalSupersaturation,
     "equilibrium supersaturation": lambda _, __: EquilibriumSupersaturation,
     "wet to critical volume ratio": lambda _, __: WetToCriticalVolumeRatio,
+    "water mass": lambda _, __: WaterMass,
 }
 
 

PySDM/attributes/physics/__init__.py

@@ -8,6 +8,7 @@
 from .dry_volume import DryVolume
 from .equilibrium_supersaturation import EquilibriumSupersaturation
 from .heat import Heat
+from .mass import WaterMass
 from .multiplicities import Multiplicities
 from .radius import Radius, SquareRootOfRadius
 from .relative_fall_velocity import RelativeFallMomentum, RelativeFallVelocity

PySDM/attributes/physics/mass.py

@@ -0,0 +1,11 @@
+"""
+particle mass, derived attribute for coalescence
+in simulation involving mixed-phase clouds, positive values correspond to
+liquid water and negative values to ice
+"""
+from PySDM.attributes.impl import ExtensiveAttribute
+
+
+class WaterMass(ExtensiveAttribute):
+    def __init__(self, builder):
+        super().__init__(builder, name="water mass")

PySDM/attributes/physics/relative_fall_velocity.py

@@ -14,15 +14,13 @@ def __init__(self, builder):
 class RelativeFallVelocity(DerivedAttribute):
     def __init__(self, builder):
         self.momentum = builder.get_attribute("relative fall momentum")
-        self.volume = builder.get_attribute("volume")
-        self.rho_w = builder.formulae.constants.rho_w  # TODO #798
+        self.water_mass = builder.get_attribute("water mass")
 
         super().__init__(
             builder,
             name="relative fall velocity",
-            dependencies=(self.momentum, self.volume),
+            dependencies=(self.momentum, self.water_mass),
         )
 
     def recalculate(self):
-        self.data.ratio(self.momentum.get(), self.volume.get())
-        self.data[:] *= 1 / self.rho_w  # TODO #798
+        self.data.ratio(self.momentum.get(), self.water_mass.get())

PySDM/attributes/physics/volume.py

@@ -1,11 +1,15 @@
 """
-particle (wet) volume, key attribute for coalescence
+particle volume (derived from water mass);
 in simulation involving mixed-phase clouds, positive values correspond to
 liquid water and negative values to ice
 """
-from PySDM.attributes.impl.extensive_attribute import ExtensiveAttribute
+from PySDM.attributes.impl import DerivedAttribute
 
 
-class Volume(ExtensiveAttribute):
+class Volume(DerivedAttribute):
     def __init__(self, builder):
-        super().__init__(builder, name="volume")
+        self.water_mass = builder.get_attribute("water mass")
+        super().__init__(builder, name="volume", dependencies=(self.water_mass,))
+
+    def recalculate(self):
+        self.particulator.backend.volume_of_water_mass(self.data, self.water_mass.get())

PySDM/backends/impl_common/freezing_attributes.py

@@ -5,15 +5,15 @@
 
 
 class SingularAttributes(
-    namedtuple("SingularAttributes", ("freezing_temperature", "wet_volume"))
+    namedtuple("SingularAttributes", ("freezing_temperature", "water_mass"))
 ):
     """groups attributes required in singular regime"""
 
     __slots__ = ()
 
 
 class TimeDependentAttributes(
-    namedtuple("TimeDependentAttributes", ("immersed_surface_area", "wet_volume"))
+    namedtuple("TimeDependentAttributes", ("immersed_surface_area", "water_mass"))
 ):
     """groups attributes required in time-dependent regime"""