Simulation Study on Impacts of Viaduct Height on Pollutant Dispersion in Street Canyons Using LES and RANS Models

Xu, R.; Chen, T.; Fu, Y. X.; Chen, J. C.; Liu, Y. H.

doi:10.47176/jafm.17.12.2594

Simulation Study on Impacts of Viaduct Height on Pollutant Dispersion in Street Canyons Using LES and RANS Models

Document Type : Regular Article

Authors

¹ Guangdong Provincial Key Laboratory of Intelligent Transportation System, School of Intelligent Systems Engineering, Shenzhen Campus of Sun Yat-sen University, Shenzhen, Guangdong, 518107, China

² School of Civil and Transportation Engineering, Guangdong University of Technology, Guangzhou, Guangdong, 510006, China

10.47176/jafm.17.12.2594

Abstract

To assess the impact of different heights of the viaduct on air pollutant dispersion and the prediction accuracy of pollutant concentration in urban street canyons, simulation results based on LES and RANS models are analyzed. The presence of a viaduct generated a poorly ventilated region underneath it, and RANS significantly underestimated the wind speed and grossly overestimated the pollutant concentration. LES gives better results for the flow pattern, distribution of turbulent kinetic energy and mean pollutant concentration. With a fluctuation of less than 15% of the pollutant concentration, both RANS and LES cases show that an increase in the viaduct height has a weak impact on the concentration of pollutants in most areas of the canyon except windward, and cases with a viaduct height of 0.75H had the lowest predicted pollutant concentration relative to other cases with a viaduct as a result of better ventilation. In addition, LES found a subregion of pollutant accumulation above the ground, but RANS did not.

Keywords

Main Subjects

Turbulent Flows

References

Allegrini, J. (2018). A wind tunnel study on three-dimensional buoyant flows in street canyons with different roof shapes and building lengths. Building and Environment, 143, 71–88. https://doi.org/10.1016/j.buildenv.2018.06.056

Baik, J. J., & Kim, J. J. (1999). A Numerical study of flow and pollutant dispersion characteristics in urban street canyons. Journal of Applied Meteorology and Climatology, 38(11), 1576–1589. https://doi.org/10.1175/1520-0450(1999)038<1576:ANSOFA>2.0.CO;2

Bouarbi, L., Abed, B., & Bouzit, M. (2016). Computational analysis of pollutant dispersion in urban street canyons with tree planting influenced by building roof shapes. Wind and Structures, 23(6), 505–521. https://doi.org/10.12989/was.2016.23.6.505

Breuer, M., Jovičić, N., & Mazaev, K. (2003). Comparison of DES, RANS and LES for the separated flow around a flat plate at high incidence. International Journal for Numerical Methods in Fluids, 41(4), 357–388. https://doi.org/10.1002/fld.445

Chang, C. H., & Meroney, R. N. (2003). Concentration and flow distributions in urban street canyons: Wind tunnel and computational data. Journal of Wind Engineering and Industrial Aerodynamics, 91(9), 1141–1154. https://doi.org/10.1016/S0167-6105(03)00056-4

Chatzimichailidis, A. E., Argyropoulos, C. D., Assael, M. J., & Kakosimos, K. E. (2019). Qualitative and quantitative investigation of multiple large eddy simulation aspects for pollutant dispersion in street canyons using OpenFOAM. Atmosphere, 10(1). https://doi.org/10.3390/atmos10010017

Chew, L. W., Aliabadi, A. A., & Norford, L. K. (2018a). Flows across high aspect ratio street canyons: Reynolds number independence revisited. Environmental Fluid Mechanics, 18(5), 1275–1291. https://doi.org/10.1007/s10652-018-9601-0

Chew, L. W., Glicksman, L. R., & Norford, L. K. (2018b). Buoyant flows in street canyons: Comparison of RANS and LES at reduced and full scales. Building and Environment, 146, 77–87. https://doi.org/10.1016/j.buildenv.2018.09.026

Ding, S., Huang, Y., Cui, P., Wu, J., Li, M., & Liu, D. (2019). Impact of viaduct on flow reversion and pollutant dispersion in 2D urban street canyon with different roof shapes—Numerical simulation and wind tunnel experiment. Science of The Total Environment, 671, 976–991. https://doi.org/10.1016/j.scitotenv.2019.03.391

Eliasson, I., Offerle, B., Grimmond, C. S. B., & Lindqvist, S. (2006). Wind fields and turbulence statistics in an urban street canyon. Atmospheric Environment, 40(1), 1–16. https://doi.org/10.1016/j.atmosenv.2005.03.031

Gousseau, P., Blocken, B., Stathopoulos, T., & van Heijst, G. J. F. (2011). CFD simulation of near-field pollutant dispersion on a high-resolution grid: A case study by LES and RANS for a building group in downtown Montreal. Atmospheric Environment, 45(2), 428–438. https://doi.org/10.1016/j.atmosenv.2010.09.065

Gromke, C. B. (2013). A database for the validation of street canyon dispersion models. Proceedings of the 15th International Conference on Harmonisation within Atmospheric Dispersion Modelling for Regulatory Purposes (HARMO), May 6-9, 2013, Madrid, Spain. https://research.tue.nl/en/publications/codasc-a-database-for-the-validation-of-street-canyon-dispersion-

Gromke, C., & Ruck, B. (2007). Influence of trees on the dispersion of pollutants in an urban street canyon-Experimental investigation of the flow and concentration field. Atmospheric Environment, 41(16), 3287–3302. https://doi.org/10.1016/j.atmosenv.2006.12.043

Gromke, C., & Ruck, B. (2009). On the impact of trees on dispersion processes of traffic emissions in street canyons. Boundary-Layer Meteorology, 131(1), 19–34. Scopus. https://doi.org/10.1007/s10546-008-9301-2

Gu, Z. L., Zhang, Y. W., Cheng, Y., & Lee, S. C. (2011). Effect of uneven building layout on air flow and pollutant dispersion in non-uniform street canyons. Building and Environment, 46(12), 2657–2665. https://doi.org/10.1016/j.buildenv.2011.06.028

Hang, J., Buccolieri, R., Yang, X., Yang, H., Quarta, F., & Wang, B. (2019). Impact of indoor-outdoor temperature differences on dispersion of gaseous pollutant and particles in idealized street canyons with and without viaduct settings. Building Simulation, 12(2), 285–297. Scopus. https://doi.org/10.1007/s12273-018-0476-2

Hang, J., Li, Y., Sandberg, M., Buccolieri, R., & Di Sabatino, S. (2012). The influence of building height variability on pollutant dispersion and pedestrian ventilation in idealized high-rise urban areas. Building and Environment, 56, 346–360. Scopus. https://doi.org/10.1016/j.buildenv.2012.03.023

Hang, J., Lin, M., Wong, D. C., Wang, X., Wang, B., & Buccolieri, R. (2016). On the influence of viaduct and ground heating on pollutant dispersion in 2D street canyons and toward single-sided ventilated buildings. Atmospheric Pollution Research, 7(5), 817–832. Scopus. https://doi.org/10.1016/j.apr.2016.04.009

Hang, J., Luo, Z., Wang, X., He, L., Wang, B., & Zhu, W. (2017). The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons. Environmental Pollution, 220, 72–86. https://doi.org/10.1016/j.envpol.2016.09.024

Hang, J., Xian, Z., Wang, D., Mak, C. M., Wang, B., & Fan, Y. (2018). The impacts of viaduct settings and street aspect ratios on personal intake fraction in three-dimensional urban-like geometries. Building and Environment, 143, 138–162. Scopus. https://doi.org/10.1016/j.buildenv.2018.07.001

Hayati, A. N., Stoll, R., Pardyjak, E. R., Harman, T., & Kim, J. J. (2019). Comparative metrics for computational approaches in non-uniform street-canyon flows. Building and Environment, 158, 16–27. https://doi.org/10.1016/j.buildenv.2019.04.028

He, L., Hang, J., Wang, X., Lin, B., Li, X., & Lan, G. (2017). Numerical investigations of flow and passive pollutant exposure in high-rise deep street canyons with various street aspect ratios and viaduct settings. Science of the Total Environment, 584-585, 189–206. https://doi.org/10.1016/j.scitotenv.2017.01.138

Huang, X., Wang, H., & Gao, L. (2023). Numerical simulation of airflow and dispersion in 3D street canyons: The effect of atmospheric temperature stratification. Environmental Technology, 44(17), 2563–2580. https://doi.org/10.1080/09593330.2022.2036247

Jon, K. S., Huang, Y., Sin, C. H., Cui, P., & Luo, Y. (2023a). Influence of wind direction on the ventilation and pollutant dispersion in different 3D street canyon configurations: Numerical simulation and wind-tunnel experiment. Environmental Science and Pollution Research, 30(11), 31647–31675. https://doi.org/10.1007/s11356-022-24212-0

Jon, K. S., Luo, Y., Sin, C. H., Cui, P., Huang, Y., & Tokgo, J. (2023b). Impacts of wind direction on the ventilation and pollutant dispersion of 3D street canyon with balconies. Building and Environment, 230, 110034. https://doi.org/10.1016/j.buildenv.2023.110034

Joerger, V. M., & Pryor, S. C. (2018). Ultrafine particle number concentrations and size distributions around an elevated highway viaduct. Atmospheric Pollution Research, 9(4), 714–722. https://doi.org/10.1016/j.apr.2018.01.008

Kastner-Klein, P., & Plate, E. J. (1999). Wind-tunnel study of concentration fields in street canyons. Atmospheric Environment, 33(24), 3973–3979. https://doi.org/10.1016/S1352-2310(99)00139-9

Kikumoto, H., & Ooka, R. (2012). A study on air pollutant dispersion with bimolecular reactions in urban street canyons using large-eddy simulations. Journal of Wind Engineering and Industrial Aerodynamics, 104–106, 516–522. https://doi.org/10.1016/j.jweia.2012.03.001

Kim, K. H., Kabir, E., & Kabir, S. (2015). A review on the human health impact of airborne particulate matter. Environment International, 74, 136–143. https://doi.org/10.1016/j.envint.2014.10.005

Kumar, P., Garmory, A., Ketzel, M., Berkowicz, R., & Britter, R. (2009). Comparative study of measured and modelled number concentrations of nanoparticles in an urban street canyon. Atmospheric Environment, 43(4), 949–958. https://doi.org/10.1016/j.atmosenv.2008.10.025

Li, X. X., Liu, C. H., & Leung, D. Y. C. (2008). Large-eddy simulation of flow and pollutant dispersion in high-aspect-ratio urban street canyons with wall model. Boundary-Layer Meteorology, 129(2), 249–268. https://doi.org/10.1007/s10546-008-9313-y

Li, X.-X., Liu, C.-H., Leung, D. Y. C., & Lam, K. M. (2006). Recent progress in CFD modelling of wind field and pollutant transport in street canyons. Atmospheric Environment, 40(29), 5640–5658. https://doi.org/10.1016/j.atmosenv.2006.04.055

Li, X.-X., Britter, R., & Norford, L. K. (2016). Effect of stable stratification on dispersion within urban street canyons: A large-eddy simulation. Atmospheric Environment, 144, 47–59. https://doi.org/10.1016/j.atmosenv.2016.08.069

Li, Z., Cai, C., Huang, X., Dou, H., Fang, W., & Ming, T. (2018). Numerical simulation on the effect of viaduct settings on the air flow and pollutants dispersion in the deep street canyon. Research of Environmental Sciences, 31(2), 254–264. https://doi.org/10.13198/j.issn.1001-6929.2017.03.73

Liu, Y., Ding, H., Chang, S., Lu, R., Zhong, H., Zhao, N., Lin, T. H., Bao, Y., Yap, L., Xu, W., Wang, M., Li, Y., Qin, S., Zhao, Y., Geng, X., Wang, S., Chen, E., Yu, Z., Chan, T. C., & Liu, S. (2020). Exposure to air pollution and scarlet fever resurgence in China: A six-year surveillance study. Nature Communications, 11(1), https://doi.org/10.1038/s41467-020-17987-8

Llaguno-Munitxa, M., Bou-Zeid, E., & Hultmark, M. (2017). The influence of building geometry on street canyon air flow: Validation of large eddy simulations against wind tunnel experiments. Journal of Wind Engineering and Industrial Aerodynamics, 165, 115–130. https://doi.org/10.1016/j.jweia.2017.03.007

Longo, R., Bellemans, A., Derudi, M., & Parente, A. (2020). A multi-fidelity framework for the estimation of the turbulent Schmidt number in the simulation of atmospheric dispersion. Building and Environment, 185, 107066. https://doi.org/10.1016/j.buildenv.2020.107066

Mei, S. J., Luo, Z., Zhao, F. Y., & Wang, H. Q. (2019). Street canyon ventilation and airborne pollutant dispersion: 2-D versus 3-D CFD simulations. Sustainable Cities and Society, 50, 101700. https://doi.org/10.1016/j.scs.2019.101700

Meroney, R. N., Pavageau, M., Rafailidis, S., & Schatzmann, M. (1996). Study of line source characteristics for 2-D physical modelling of pollutant dispersion in street canyons. Journal of Wind Engineering and Industrial Aerodynamics, 62(1), 37–56. https://doi.org/10.1016/S0167-6105(96)00057-8

Ming, T., Nie, C., Li, W., Kang, X., Wu, Y., Zhang, M., & Peng, C. (2022). Numerical study of reactive pollutants diffusion in urban street canyons with a viaduct. Building Simulation, 15(7), 1227–1241. https://doi.org/10.1007/s12273-021-0795-6

Moonen, P., Gromke, C., & Dorer, V. (2013). Performance assessment of Large Eddy Simulation (LES) for modeling dispersion in an urban street canyon with tree planting. Atmospheric Environment, 75, 66–76. https://doi.org/10.1016/j.atmosenv.2013.04.016

Ng, W. -Y., & Chau, C.-K. (2014). A modeling investigation of the impact of street and building configurations on personal air pollutant exposure in isolated deep urban canyons. Science of The Total Environment, 468–469, 429–448. https://doi.org/10.1016/j.scitotenv.2013.08.077

Nguyen, V. T., Nguyen, T. C., & Nguyen, J. (2019). Numerical simulation of turbulent flow and pollutant dispersion in urban street canyons. Atmosphere, 10(11). https://doi.org/10.3390/atmos10110683

Pu, Y., & Yang, C. (2014). Estimating urban roadside emissions with an atmospheric dispersion model based on in-field measurements. Environmental Pollution, 192, 300–307. https://doi.org/10.1016/j.envpol.2014.05.019

Oachim & Ichhorn (2004). Simulation of effects of vegetation on the dispersion of pollutants in street canyons. https://www.semanticscholar.org/paper/Simulation-of-effects-of-vegetation-on-the-of-in-Oachim-Ichhorn/9d91b7d7bdfc0ea930cc4a5963cd7b5e3e88e943

Qin, C., Song, C., Wang, S., & Zhao, J. (2018). Numerical study on the air environment of ideal street valley with double viaduct in vertical windward. Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae, 38(9), 3467–3474. https://doi.org/10.13671/j.hjkxxb.2018.0154

Rossi, R., & Iaccarino, G. (2009). Numerical simulation of scalar dispersion downstream of a square obstacle using gradient-transport type models. Atmospheric Environment, 43(16), 2518–2531. https://doi.org/10.1016/j.atmosenv.2009.02.044

Salim, S. M., & Ong, K. C. (2013). Performance of RANS, URANS and LES in the prediction of airflow and pollutant dispersion. In H. K. Kim, S. I. Ao, & B. B. Rieger (Eds.), IAENG transactions on engineering technologies: Special edition of the world congress on engineering and computer science 2011 (pp. 263–274). Springer Netherlands. https://doi.org/10.1007/978-94-007-4786-9_21

Salim, S. M., Buccolieri, R., Chan, A., & Di Sabatino, S. (2011a). Numerical simulation of atmospheric pollutant dispersion in an urban street canyon: Comparison between RANS and LES. Journal of Wind Engineering and Industrial Aerodynamics, 99(2–3), 103–113. https://doi.org/10.1016/j.jweia.2010.12.002

Salim, S. M., Cheah, S. C., & Chan, A. (2011b). Numerical simulation of dispersion in urban street canyons with avenue-like tree plantings: Comparison between RANS and LES. Building and Environment, 46(9), 1735–1746. https://doi.org/10.1016/j.buildenv.2011.01.032

Shao, J., & Zhang, C. (2006). Numerical analysis of the flow around a circular cylinder using RANS and LES. International Journal of Computational Fluid Dynamics, 20(5), 301–307. https://doi.org/10.1080/10618560600898437

So, E. S. P., Chan, A. T. Y., & Wong, A. Y. T. (2005). Large-eddy simulations of wind flow and pollutant dispersion in a street canyon. Atmospheric Environment, 39(20), 3573–3582. https://doi.org/10.1016/j.atmosenv.2005.02.044

Takano, Y., & Moonen, P. (2013). On the influence of roof shape on flow and dispersion in an urban street canyon. Journal of Wind Engineering and Industrial Aerodynamics, 123, 107–120. https://doi.org/10.1016/j.jweia.2013.10.006

Tominaga, Y., & Stathopoulos, T. (2013). CFD simulation of near-field pollutant dispersion in the urban environment: A review of current modeling techniques. Atmospheric Environment, 79, 716–730. https://doi.org/10.1016/j.atmosenv.2013.07.028

Toparlar, Y., Blocken, B., Maiheu, B., & van Heijst, G. J. F. (2017). A review on the CFD analysis of urban microclimate. Renewable and Sustainable Energy Reviews, 80, 1613–1640. https://doi.org/10.1016/j.rser.2017.05.248

van Hooff, T., Blocken, B., & Tominaga, Y. (2017). On the accuracy of CFD simulations of cross-ventilation flows for a generic isolated building: Comparison of RANS, LES and experiments. Building and Environment, 114, 148–165. https://doi.org/10.1016/j.buildenv.2016.12.019

Wong, C. C. C., & Liu, C. H. (2014). Large-eddy simulation of flows over two-dimensional idealised street canyons with height variation. International Journal of Environment and Pollution, 54(2/3/4), 147. https://doi.org/10.1504/IJEP.2014.065115

Zhang, C., Wen, M., Zeng, J., Zhang, G., Fang, H., & Li, Y. (2012). Modeling the impact of the viaduct on particles dispersion from vehicle exhaust in street canyons. Science China Technological Sciences, 55(1), 48–55. https://doi.org/10.1007/s11431-011-4610-y

Zhang, K., Chen, G., Wang, X., Liu, S., Mak, C. M., Fan, Y., & Hang, J. (2019). Numerical evaluations of urban design technique to reduce vehicular personal intake fraction in deep street canyons. Science of the Total Environment, 653, 968–994. https://doi.org/10.1016/j.scitotenv.2018.10.333

Zhang, Y., Gu, Z., & Yu, C. W. (2018). Review on numerical simulation of airflow and pollutant dispersion in urban street canyons under natural background wind condition. Aerosol and Air Quality Research, 18(3), 780–789. https://doi.org/10.4209/aaqr.2017.09.0303

Zheng, X., & Yang, J. (2021). CFD simulations of wind flow and pollutant dispersion in a street canyon with traffic flow: Comparison between RANS and LES. Sustainable Cities and Society, 75, 103307. https://doi.org/10.1016/j.scs.2021.103307

Zhou, B., Zhao, B., Guo, X., Chen, R., & Kan, H. (2013). Investigating the geographical heterogeneity in PM10-mortality associations in the china air pollution and health effects study (CAPES): A potential role of indoor exposure to PM10 of outdoor origin. Atmospheric Environment, 75, 217–223. https://doi.org/10.1016/j.atmosenv.2013.04.044