Can deeper street canyons ventilate better? An analysis of roof geometries and aspect ratios with a focus on pollutant dynamics

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61388998%3A_____%2F25%3A00603891" target="_blank" >RIV/61388998:_____/25:00603891 - isvavai.cz</a>

Nalezeny alternativní kódy

RIV/00216208:11320/25:10495587

Výsledek na webu

<a href="https://www.sciencedirect.com/science/article/pii/S0360132325000101?dgcid=author" target="_blank" >https://www.sciencedirect.com/science/article/pii/S0360132325000101?dgcid=author</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.buildenv.2025.112528" target="_blank" >10.1016/j.buildenv.2025.112528</a>

Jazyk výsledku

angličtina

Název v původním jazyce

Can deeper street canyons ventilate better? An analysis of roof geometries and aspect ratios with a focus on pollutant dynamics

Popis výsledku v původním jazyce

This study addresses ventilation and pollutant transport in urban street canyons with different roof geometries and canyon aspect ratios using Detached Eddy Simulation (DES). First, we validated the DES through wind tunnel experiments on flow and pollutant dispersion in two different street canyon models with different aspect ratios (AR1 and AR2), but both with flat roofs (F-AR1 and F-AR2). Then we performed the DES on two more models with the same aspect ratios as the previous ones but with pitched roofs (P-AR1 and P-AR2). The results show that deeper street canyons (F-AR2 and P-AR2) are more efficiently ventilated at higher levels than shallower street canyons (F-AR1 and P-AR1), mainly due to the outflow of pollutants through lateral openings. Street canyons with pitched roofs (P-AR1 and P-AR2) improve ventilation by a factor of 2, as pollutant removal by advection through the top and side openings is significantly higher than in street canyons with flat roofs. We have found that the P-AR2 street canyon is the best configuration for adequate pollutant ventilation in the pedestrian zone. This configuration provides cleaner air at the leeward and windward walls compared to the street canyon P-AR1. The dynamic mode decomposition (DMD) shows that the propagation of turbulent coherent structures correlates with the propagation of concentration structures and pollutant advection. However, advection improves the ventilation of street canyons compared to turbulent coherent structures, especially through lateral openings. These results provide valuable insights for the design of street canyons and suggest that deeper street canyons with pitched roofs can provide better air quality in the pedestrian zone and especially at higher street levels.

Název v anglickém jazyce

Can deeper street canyons ventilate better? An analysis of roof geometries and aspect ratios with a focus on pollutant dynamics

Popis výsledku anglicky

This study addresses ventilation and pollutant transport in urban street canyons with different roof geometries and canyon aspect ratios using Detached Eddy Simulation (DES). First, we validated the DES through wind tunnel experiments on flow and pollutant dispersion in two different street canyon models with different aspect ratios (AR1 and AR2), but both with flat roofs (F-AR1 and F-AR2). Then we performed the DES on two more models with the same aspect ratios as the previous ones but with pitched roofs (P-AR1 and P-AR2). The results show that deeper street canyons (F-AR2 and P-AR2) are more efficiently ventilated at higher levels than shallower street canyons (F-AR1 and P-AR1), mainly due to the outflow of pollutants through lateral openings. Street canyons with pitched roofs (P-AR1 and P-AR2) improve ventilation by a factor of 2, as pollutant removal by advection through the top and side openings is significantly higher than in street canyons with flat roofs. We have found that the P-AR2 street canyon is the best configuration for adequate pollutant ventilation in the pedestrian zone. This configuration provides cleaner air at the leeward and windward walls compared to the street canyon P-AR1. The dynamic mode decomposition (DMD) shows that the propagation of turbulent coherent structures correlates with the propagation of concentration structures and pollutant advection. However, advection improves the ventilation of street canyons compared to turbulent coherent structures, especially through lateral openings. These results provide valuable insights for the design of street canyons and suggest that deeper street canyons with pitched roofs can provide better air quality in the pedestrian zone and especially at higher street levels.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10509 - Meteorology and atmospheric sciences

Projekt

<a href="/cs/project/GA22-14608S" target="_blank" >GA22-14608S: Role dynamiky koherentních struktur na přenos a rozptyl skaláru v městském baldachýnu</a><br>

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2025

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název periodika

Building and Environment

ISSN

0360-1323

e-ISSN

1873-684X

Svazek periodika

270

Číslo periodika v rámci svazku

February

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

17

Strana od-do

112528

Kód UT WoS článku

001410178400001

EID výsledku v databázi Scopus

2-s2.0-85214328341