Large-Eddy Simulation Analyses of Heated Urban Canyon Facades

Abstract

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.

Computational Examination of Heat and Mass Transfer Induced by Ternary Nanofluid Flow across Convergent/Divergent Channels with Pollutant Concentration

“…From the Equations ( 2) and ( 3) we can eliminate the pressure term by utilizing ( 10) and (11), we obtain,…”

“…Chinyoka and Makinde [10] explore the dynamics of polymeric pollutant dispersion in a rectangular channel, caused by an external source in a flowing Newtonian liquid, the numerical model provides insights into pollution scenarios resulting from an improper discharge of hydrocarbon products offering measurements for detecting contamination levels. The study initiated by Cintolesi et al [11] focuses on the interaction between inertial and thermal forces in urban canyons and their impact on turbulent characteristics and pollutant removal. Large-eddy simulations model the square canyons with different facade temperatures, while a street-level scalar source represents traffic emissions.…”

A Model Development for Thermal and Solutal Transport Analysis of Non-Newtonian Nanofluid Flow over a Riga Surface Driven by a Waste Discharge Concentration

“…Makinde et al [34] studied pollutant transportation in rivers using partial differential equations. Cintolasi et al [35] scrutinized the complicated connection between heat and inertial factors within the canyon, especially the effects on turbulence characteristics and pollution remediation techniques. Chinyoka and Makinde [36] examined the nonlinear spreading of a pollutant released by an external source through the laminar liquid circulation of an incompressible liquid in a channel.…”

Scrutinization of Waste Discharge Concentrations in Eyring-Powell Nanofluid Past a Deformable Horizontal Plane Surface

“…The recently created field of nanotechnology is currently offering an intriguing way of purifying water with affordable prices, significant operating efficacy in removing contaminants, and recycling ability [5]. Cintolesi et al [6] focused on the interface of thermal and inertial forces in urban canyons and how these forces affect turbulent properties and pollution removal. Chinyoka and Makinde [7] investigated the kinetics of polymeric pollutant dispersal of Newtonian fluid flow through a rectangular channel.…”