CFD simulation of the effect of an upstream building on the inter-unit dispersion in a multi-story building in two wind directions

Abstract Previous studies on inter-unit dispersion are limited to isolated buildings. The influence of an upstream interfering building may significantly modify the indoor airflow characteristics of the wind-induced natural ventilated downstream interfered building. Motivated by the findings in previous studies, namely that infectious respiratory aerosols exhausted from a unit can re-enter into another unit in the same building through building envelope openings, this study investigates the inter-unit pollutant dispersion around a multi-story building in two wind directions by employing the computational fluid dynamics (CFD) method. The CFD model employed in this study has been validated against previous experimental data. The results show that the presence of an upstream building greatly changes the path lines around the downstream target building and the pollutant transportation routes around it. The presence of a low upstream building also greatly increases the average air exchange rate (ACH) values and the pollutant re-entry ratios (R k ) below the source unit on the windward side of the downstream target building for normal wind incidence. However, the presence of a high upstream building greatly increases the average ACH values on the windward side and increases the R k on the leeward side of the downstream building for oblique wind incidence.

[1]  Kit Ming Lam,et al.  Recent progress in CFD modelling of wind field and pollutant transport in street canyons , 2006 .

[2]  Nicolas G. Wright,et al.  On the use of the k–ε model in commercial CFD software to model the neutral atmospheric boundary layer , 2007 .

[3]  K. Pericleous,et al.  Modelling air quality in street canyons : a review , 2003 .

[4]  Ming Gu,et al.  Numerical simulations of wind pressures on buildings in staggered arrangement , 2006 .

[5]  M. Sandberg,et al.  Building Ventilation: Theory and Measurement , 1996 .

[6]  Shuzo Murakami,et al.  3-D numerical simulation of airflow around a cubic model by means of the k-ϵ model , 1988 .

[7]  Cheuk Ming Mak,et al.  From street canyon microclimate to indoor environmental quality in naturally ventilated urban buildings: Issues and possibilities for improvement , 2015, Building and Environment.

[8]  G. T. Johnson,et al.  Some insights into typical urban canyon airflows , 1999 .

[9]  Cheuk Ming Mak,et al.  A study of interunit dispersion around multistory buildings with single-sided ventilation under different wind directions , 2014 .

[10]  Yoshihide Tominaga,et al.  Turbulent Schmidt numbers for CFD analysis with various types of flowfield , 2007 .

[11]  Cheuk Ming Mak,et al.  CFD simulation of flow and dispersion around an isolated building: Effect of inhomogeneous ABL and near-wall treatment , 2013 .

[12]  Cheuk Ming Mak,et al.  Large eddy simulation of wind‐induced interunit dispersion around multistory buildings , 2015, Indoor air.

[13]  Theodore Stathopoulos,et al.  Numerical evaluation of pollutant dispersion in the built environment: comparisons between models and experiments , 2008 .

[14]  Theodore Stathopoulos,et al.  Near-field pollutant dispersion in the built environment by CFD and wind tunnel simulations , 2011 .

[15]  D. Grawe,et al.  BEST PRACTICE GUIDELINE FOR THE CFD SIMULATION OF FLOWS IN THE URBAN ENVIRONMENT , 2007 .

[16]  P. Heiselberg,et al.  The airborne transmission of infection between flats in high-rise residential buildings: Tracer gas simulation , 2007, Building and Environment.

[17]  J Niu,et al.  On-site quantification of re-entry ratio of ventilation exhausts in multi-family residential buildings and implications. , 2007, Indoor air.

[18]  Mats Sandberg,et al.  The influence of building height variability on pollutant dispersion and pedestrian ventilation in idealized high-rise urban areas , 2012 .

[19]  Jörg Franke,et al.  The COST 732 Best Practice Guideline for CFD simulation of flows in the urban environment: a summary , 2011 .

[20]  J. Monteith,et al.  Boundary Layer Climates. , 1979 .

[21]  C. Mann,et al.  A Practical Treatise on Diseases of the Skin , 1889, Atlanta Medical and Surgical Journal (1884).

[22]  Theodore Stathopoulos,et al.  The effect of upstream buildings on near-field pollutant dispersion in the built environment , 2011 .

[23]  H Hamid Montazeri,et al.  CFD simulation of wind-induced pressure coefficients on buildings with and without balconies: Validation and sensitivity analysis , 2013 .

[24]  Cheuk Ming Mak,et al.  The Effect of Balconies on Ventilation Performance of Low-rise Buildings , 2011 .

[25]  Cheuk Ming Mak,et al.  Effect of balconies and upper–lower vents on ventilation and indoor air quality in a wind-induced, naturally ventilated building , 2014 .

[26]  Cheuk Ming Mak,et al.  The assessment of the performance of balconies using computational fluid dynamics , 2011 .

[27]  Yoshihide Tominaga,et al.  CFD modeling of pollution dispersion in a street canyon: Comparison between LES and RANS , 2011 .

[28]  Yoshihide Tominaga,et al.  AIJ guidelines for practical applications of CFD to pedestrian wind environment around buildings , 2008 .

[29]  Robert N. Meroney,et al.  Concentration and flow distributions in urban street canyons: wind tunnel and computational data , 2003 .

[30]  Z T Ai,et al.  Numerical investigation of wind-induced airflow and interunit dispersion characteristics in multistory residential buildings. , 2013, Indoor air.

[31]  Y. Li,et al.  Multi-zone modeling of probable SARS virus transmission by airflow between flats in Block E, Amoy Gardens. , 2005, Indoor air.