The effect of turbulence induced by different kinds of moving vehicles in street canyons

Review on pollutant dispersion in urban areas-part A: Effects of mechanical factors and urban morphology

“…Cai et al [140] investigated the relationship between TPT and vehicle shape. The results indicated that a truck produced more TKE than a car or SUV in the canyons (Fig.…”

“…Furthermore, a high turbulence level can contribute to the mixing of pollutants and creates a more uniform pollutant distribution at the pedestrian level. The traffic composition changes the distribution of TPF and TPT, and the effect is more pronounced for TPF; the passive gaseous pollutant concentration of twoway traffic at the pedestrian level was almost 44% higher than that of one-way traffic [140] a, b, c S (H/W = 1) CFD (V) A truck produced more TKE than a car or SUV in the canyons…”

“…Fig. 9 (a) TKE contours across the centerline of vehicles at different velocities [137]; (b) normalized concentration at a reference point (leeward canyon wall, ground level) as a function of the velocity ratio v (vehicle moving speed) /u(reference wind speed); the traffic density is expressed by the scaling factor a [131]; (c) TKE profiles at different vehicle speeds and different distances to the opposing roadway (L=5, 15, 50 m) [138];(d) concentration patterns at the leeward canyon wall for different traffic conditions[131]; (e) TKE distribution at the center height of the vehicle for different vehicle shapes[140].…”

Introducing the Green Infrastructure for Roadside Air Quality (GI4RAQ) Platform: Estimating Site-Specific Changes in the Dispersion of Vehicular Pollution Close to Source

“…Moving vehicles also disrupt the flow of air within a street. They increase turbulent mixing in their wake (perturbing any building-induced patterns of advection) and introduce an additional advective component orthogonal to the recirculation (drawing their emissions along the street; see, e.g., [67][68][69]). The trial of a new, ultrafast chemiluminescence detector, permitting NO x measurements up to 500 times a second, has also revealed the potential for following vehicles to displace emissions from leading vehicles laterally [70], i.e., from one side of the road to the other and/or towards the roadside.…”

The effect of exhaust emissions from a group of moving vehicles on pollutant dispersion in the street canyons

“…In vehicle wake, the TKE induced by the vehicle with speed of 15 m/s is about 6.3 times and 1.8 times greater than that induced by the vehicle with the speed of 5 m/s and 10 m/s, respectively. Cai [39] used a dynamic mesh updating method to analyze the TKE induced by a single vehicle under various wind directions and vehicle types. The results showed that the wind direction has an obvious impact on the VIT.…”