Large-Eddy Simulation Analyses of Heated Urban Canyon Facades

Thermal convective flows are common phenomena in real urban canyons and strongly affect the mechanisms of pollutant removal from the canyon. The present contribution aims at investigating the complex interaction between inertial and thermal forces within the canyon, including the impacts on turbulen...

Full description

Saved in:
Bibliographic Details
Published in:Energies (Basel) 2021-06, Vol.14 (11), p.3078
Main Authors: Cintolesi, Carlo, Barbano, Francesco, Di Sabatino, Silvana
Format: Article
Language:English
Subjects:
Building facades
Canyons
Case studies
Computational fluid dynamics
Convection
Convection heating
Convective flow
convective flows
Facades
Fluid dynamics
Fluxes
Induction heating
Laboratories
Large eddy simulation
Morphology
Pollutant removal
Pollutants
Pollution control
Richardson number
Simulation
Street canyons
turbulence
urban canyon
Velocity
Ventilation
Vortices
Wind effects
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Thermal convective flows are common phenomena in real urban canyons and strongly affect the mechanisms of pollutant removal from the canyon. The present contribution aims at investigating the complex interaction between inertial and thermal forces within the canyon, including the impacts on turbulent features and pollutant removal mechanisms. Large-eddy simulations reproduce infinitely long square canyons having isothermal and differently heated facades. A scalar source on the street mimics the pollutant released by traffic. The presence of heated facades triggers convective flows which generate an interaction region around the canyon-ambient interface, characterised by highly energetic turbulent fluxes and an increase of momentum and mass exchange. The presence of this region of high mixing facilitates the pollutant removal across the interface and decreases the urban canopy drag. The heating-up of upwind facade determines favourable convection that strengthens the primary internal vortex and decreases the pollutant concentration of the whole canyon by 49% compare to the isothermal case. The heating-up of the downwind facade produces adverse convection counteracting the wind-induced motion. Consequently, the primary vortex is less energetic and confined in the upper-canyon area, while a region of almost zero velocity and high pollution concentration (40% more than the isothermal case) appears at the pedestrian level. Finally, numerical analyses allow a definition of a local Richardson number based on in-canyon quantities only and a new formulation is proposed to characterise the thermo-dynamics regimes.
ISSN:1996-1073
1996-1073
DOI:10.3390/en14113078