Simulation of pollutants with diffusion functions
To analyze the transport of smoke (pollutants) spreading through urban areas, we perform a simplified analysis by adding a scalar transport equation and model to existing computational fluid analysis.
We will place a virtual factory and chimney on 3D ground surface data and building cluster data (PLATEAU data) and analyze how smoke diffuses. We will add a scalar transport equation and model to the steady-state turbulence analysis solver simpleFoam. In this example, we will use the functions object in system/controlDictct to analyze the diffusion of smoke emitted from the factory using the scalar transport equation solver scalerTransport.
Model Shape
Analysis area/mesh
1.3km x 1.8km x 0.5km area
Various conditions
Velocity and turbulence profiles from the Atmospheric Boundary Layer (ABL) model are used.
The wind speed, which depends on the height direction, flows in from the inlet area (Y maximum face) and flows out from the outlet area (Y minimum face).
The ground is fixed with a velocity of 0 m/s, and the ground, building surface, and factory are in no-slip condition.
Other walls (area symmetry) are made symmetrical by including "caseDicts/setConstraintTypes ($WM_PROJECT_DIR/etc/caseDicts/setConstraintTypes)".
Calculation result
Weight density of the diffused material in the chimney cross section (C)
Wind speed at the stack cross section (U)
Streamlines of the mass density (C) of the diffusing material