Abstract:The correct prediction of air pollutants dispersed in urban areas is of paramount importance to safety, public health and a sustainable environment. Vehicular traffic is one of the main sources of nitrogen oxides (NO x ) and particulate matter (PM), strongly related to human morbidity and mortality. In this study, the pollutant level and distribution in a section of one of the main road arteries of Antwerp (Belgium, Europe) are analyzed. The assessment is performed through computational fluid dynamics (CFD), a… Show more
“…Wind catchers have been used to improve indoor air quality, however, some recent studies show that wind catchers can be effectively employed to improve outdoor air quality as well [31,32]. Located at the roof of certain buildings facing the main street, wind catchers offer a passive method of diluting the pollutant concentrations and increasing wind speed for targeted areas within urban street canyons.…”
“…Some studies have shown that lift-up building design can ally provide a comfortable microclimate in summer conditions, while not causing a cold stress in the winter [33]. Although the study characterised different building s such as the 'L', 'U', 'I' and the '□' shaped buildings in different orientations (Figure wind flow (at the pedestrian level) seems to be more altered due to the shape and ar ment of the core and column supports rather than the shape of the building itself [ Employment of wind catchers appear to reduce concentration levels by up to 37% in some pedestrian-level areas, by modifying the air entrainment in the street canyons resulting in a more efficient dilution process [31]. The benefits of wind catchers are that they can be targeted for specific buildings, while not taking up space within the urban canyon at street levels.…”
Section: Lift-up Buildings and Building Permeabilitymentioning
Many research articles explore new designs and how to arrange barriers/obstacles to improve roadside air quality and ventilation within the urban street canyon. These obstacles are generally categorized into porous, non-porous and mixed type. Porous barriers include vegetated shrubs and trees; non-porous barriers include parked cars, low boundary walls, etc., while mixed barriers combine both porous and non-porous barriers. Moreover, new developments can benefit from added design flexibility using lift-up building design and building porosity as a promising way of improving ventilation. This short paper reviews the different research studies conducted on obstacles/barriers in an urban canyon which helps improve air quality and also highlights potential future research.
“…Wind catchers have been used to improve indoor air quality, however, some recent studies show that wind catchers can be effectively employed to improve outdoor air quality as well [31,32]. Located at the roof of certain buildings facing the main street, wind catchers offer a passive method of diluting the pollutant concentrations and increasing wind speed for targeted areas within urban street canyons.…”
“…Some studies have shown that lift-up building design can ally provide a comfortable microclimate in summer conditions, while not causing a cold stress in the winter [33]. Although the study characterised different building s such as the 'L', 'U', 'I' and the '□' shaped buildings in different orientations (Figure wind flow (at the pedestrian level) seems to be more altered due to the shape and ar ment of the core and column supports rather than the shape of the building itself [ Employment of wind catchers appear to reduce concentration levels by up to 37% in some pedestrian-level areas, by modifying the air entrainment in the street canyons resulting in a more efficient dilution process [31]. The benefits of wind catchers are that they can be targeted for specific buildings, while not taking up space within the urban canyon at street levels.…”
Section: Lift-up Buildings and Building Permeabilitymentioning
Many research articles explore new designs and how to arrange barriers/obstacles to improve roadside air quality and ventilation within the urban street canyon. These obstacles are generally categorized into porous, non-porous and mixed type. Porous barriers include vegetated shrubs and trees; non-porous barriers include parked cars, low boundary walls, etc., while mixed barriers combine both porous and non-porous barriers. Moreover, new developments can benefit from added design flexibility using lift-up building design and building porosity as a promising way of improving ventilation. This short paper reviews the different research studies conducted on obstacles/barriers in an urban canyon which helps improve air quality and also highlights potential future research.
“…CFD simulation was used to optimize the circulating air volume, return air angle, and exhaust volume of the circulating system. Lauriks et al [21] used CFD to analyze the level and distribution of pollutants in a part of Antwerp's main road artery (Belgium, Europe). Erfan et al [22] investigated the influence of the crosssectional shape of a building on the diffusion of air pollutants around the isolated building.…”
Using wind speed, wind direction, and turbulence intensity values as evaluation indicators, the ventilation performance of villages with complex building layouts was studied. We used the SKE, RNG, and RKE solvers in CFD-3D steady-state Reynolds-averaged Navier–Stokes (RANS) to simulate the wind environment of a village. The findings show that for the simulation of rural wind environments with complex building layouts, steady-state simulation solvers need to be evaluated in detail to verify their accuracy. In this study, a village with a complex architectural layout in Southern Shaanxi, China, was taken as the research object, and three steady-state simulation solvers were used to evaluate the ventilation performance of the village. The simulated data were compared with the measured data to find the most suitable solver for this kind of village wind environment simulation. The results show that for the simulation of the village wind environment with a complex building layout, the RNG simulation results have the lowest reliability among the three steady-state solvers. The reliability of wind speed distribution and turbulence intensity distribution are 0.7881 and 0.2473, respectively. However, the wind speed and turbulence intensity values obtained by the SKE solver are the closest to the measured values, which are 0.8625 and 0.9088, respectively. Therefore, for villages with complex building layouts, the SKE solver should be the first choice for simulating wind environment distribution. When using the RNG solver, the overall turbulence intensity value obtained is higher than the measured value. The average deviation between the simulated data and SKE and RKE at a height of 1.7 m is 42.61%. The main reason for this is that RNG overestimates the vortices and underestimates the airflow rate in the building intervals.
“…With continued growth of computational power and advances in CFD techniques, even complex models can be done on commodity hardware. Thus, CFD modeling is routinely applied in several fields of science and engineering such as chemistry, 2,3 materials, 4 fluid flow and heat transfer, 5,6 biology, 7 drug delivery, 8 semiconductors, 9 environmental engineering, 10,11 biomedical engineering, 12 and aeronautics 13…”
Computational fluid dynamics (CFD) analysis is widely used in chemical engineering. Although CFD calculations are accurate, the computational cost associated with complex systems makes it difficult to obtain empirical equations between system variables. Here, we combine active learning (AL) and symbolic regression (SR) to get a symbolic equation for system variables from CFD simulations. Gaussian process regression‐based AL allows for automated selection of variables by selecting the most instructive points from the available range of possible parameters. The results from these experiments are then passed to SR to find empirical symbolic equations for CFD models. This approach is scalable and applicable for any desired number of CFD design parameters. To demonstrate the effectiveness, we use this method with two model systems. We recover an empirical equation for the pressure drop in a bent pipe and a new equation for predicting backflow in a heart valve under aortic insufficiency.
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