Jae‐Jin Kim

This study investigates thermal effects on the flow and pollutant dispersion in urban street canyons. A two-dimensional numerical model with a k–ϵ turbulent closure scheme is developed, and the heat transfer between the air and the building wall or street-canyon bottom is effectively represented by a wall function. For each of seven cases with different aspect ratios (building height/width between buildings = 0.5, 1, 1.5, 2, 2.5, 3, and 3.5), four thermal situations (no heating, upwind building-

In this study, we applied a computational fluid dynamics (CFD) model incorporating a tree drag parameterization scheme to investigate how the presence of trees improved pedestrian wind comfort on the urban campus of Pukyong National University (PKNU). We comprehensively analyzed pedestrian wind comfort considering wind inflow direction and observed frequency. To validate the CFD model, we conducted sensitivity simulations by varying the vertical profiles of leaf area density (LAD) and compared o

This study proposes a method for estimating wind speeds. The method determined the rate of change in wind speed associated with the morphological parameters in the urban or suburban districts by conducting multiple regression analyses. Then, it estimated wind speeds by combining the change rate and inflow wind speeds in Gangnam-gu (GD), Yangcheon-gu (YD), and Pyeongtaek City (PD). Compared to the local data assimilation and prediction system (LDAPS), the estimation method decreased the root mean

This study investigated the characteristics of the flow and dispersion of reactive pollutants in three-dimensional idealized street canyons in the presence of building-roof cooling to provide implications in how a green-roof system contributes to mitigating of pedestrian exposure to near-roadway air pollution in street canyons. The pollutant chemistry was simulated using a coupled CFD-chemistry model. In the presence of building-roof cooling, winds and temperature fields inside the building cano

Abstract We investigate the flow characteristics around step-up street canyons with various building aspect ratios (ratio of along-canyon building length to street-canyon width, and upwind building height to downwind building height) using a computational fluid dynamics (CFD) model. Simulated results are validated against experimental wind-tunnel results, with the CFD simulations conducted under the same building configurations as those in the wind-tunnel experiments. The CFD model reproduces th

Vertical forests have been constructed as environmentally friendly solutions for air quality and urban heat problems. With an expectation to provide insights into the value of vertical forests, we examined the impact of these structures on flows and distribution of fine particles in step-up street canyons using a computational fluid dynamics (CFD) model. The CFD model was rigorously validated against wind-tunnel experiments and accurately simulated particle deposition efficiency by tree leaves u