Numerical and Wind Tunnel Simulation Studies of the Flow Field and Pollutant Diffusion around a Building under Neutral and Stable Atmospheric Stratifications

Abstract

In this paper, the k–ε renormalization group (RNG) turbulence model is used to simulate the flow and dispersion of pollutants emitted from a source at the top of a cubic building under neutral and stable atmospheric stratifications, the results of which were compared with corresponding wind tunnel experiment results. When atmosphere stratification is stable, the separation zones on the sides and at the top of a building are relatively smaller than those under neutral conditions, and the effect of the building in the horizontal direction is stronger than that in the vertical direction. The variation in turbulent kinetic energy under stable conditions is significantly lower than that under neutral conditions. The effect of atmospheric stratification on the turbulent kinetic energy becomes gradually more prominent with increased distance. When atmosphere conditions are stable, the vertical distribution of the plume is smaller than that of neutral conditions, but the lateral spread and near-ground concentration are slightly larger than those of neutral conditions, mainly because stable atmospheric stratification suppresses the vertical motions of airflow and increases the horizontal spread of the plume.

Open access system of life quality management on the basis of spatial modelling of pollution in the coastal areas

“…In comparison to earlier designed scheme [8] new block of input data was added to the system -air parameters, according to recommendations of World Health Organization "Air quality guidelines", 2005, [17]: contents of solids, ozone, NO2, SO2. Also we added wind direction, because the direction and speed of wind plays an important role in the spread of pollutants in the air [18], so this factor should be seriously considered in urban planning when planning settlements and the location of industrial enterprises and residential areas [19,20]. However, it should be taken into account that during the year the winds blow in all directions, so the environment is polluted in all directions to a greater or lesser extent.…”

Air Pollution Dispersion Modelling in Urban Environment Using CFD: A Systematic Review

“…A concerning trend is observed: almost half of the reviewed publications either do not comply with the BPGs for the domain dimensions in the flow direction (e.g., [52,[55][56][57][58][59][60], reaching zero distance offsets between the domain boundaries and the outer buildings in [61]), or do not report these important domain parameters (e.g., [16,[62][63][64]). Conversely, there are articles [48,50,[65][66][67][68] where the upstream distance that was used is much higher than the minimum recommendation of 5H, ranging between 14H in [48] and 38H in [68]. The same is true for the downstream distance, which, in papers [15,48,50,[68][69][70][71] ranges from 28H in [69] to 133.3H in [50].…”

“…Conversely, there are articles [48,50,[65][66][67][68] where the upstream distance that was used is much higher than the minimum recommendation of 5H, ranging between 14H in [48] and 38H in [68]. The same is true for the downstream distance, which, in papers [15,48,50,[68][69][70][71] ranges from 28H in [69] to 133.3H in [50].…”

“…As vehicles play a significant role in urban pollution, the bulk of the reviewed cases employed a ground-level source of emission to mirror traffic pollution, as evidenced by Figure 13. Meanwhile, some articles (e.g., [58,59,68,71,73,75,[94][95][96]) investigated the dispersion of pollutant from stack sources located on top of buildings, which is an equally important factor as it can negatively influence the air quality in the surrounding areas. In contrast, the pollutant in 3 studies [87,88,90] was injected into the computational domain from the inlet plane.…”

Sensitivity study for finite element analysis on wind distribution surrounding transmission line corridors with consideration of turbulent flow

“…Therefore, CFDbased numerical simulation methods are also widely used in wind power generation calculations in wind engineering [5] and construction. Structural wind engineering [6] and complex terrain wind field simulation [7] and other aspects.…”