Numerical simulation of the influence of building‑tree arrangements on wind velocity and PM2.5 dispersion in urban communities

Airflow behavior and outdoor PM(2.5) dispersion depend significantly on the building-tree layouts and orientation towards the prevailing wind conditions. To investigate this issue, the present work evaluates the aerodynamic effect of different building-tree layouts on the outdoor PM(2.5) dispersions in the urban communities of Shijiazhuang City, China. The adopted numerical CFD technique was based on the standard k–ε model and the Disperse Phase Model (DPM). For this study, ten different building-tree arrangements were conceptualized and all these configurations were simulated by using Ansys Fluent software to quantify the implications on the outdoor PM(2.5) dispersion due to their presence. The results have shown that: (1) a wide building interval space could benefit the air ventilation and thus decrease PM(2.5) concentrations, however, this effectiveness is highly influenced by the presence of the trees; (2) the trees on the leeward side of a building tend to increase the local wind velocity and decrease the pedestrian-level PM(2.5) concentrations, while those on the windward side tend to decrease the wind velocity. The small distance with trees in the central space of the community forms a wind shelter, hindering the particle dispersion; and (3) the configuration of parallel type buildings with clustered tree layouts in the narrow central space is most unfavorable to the air ventilation, leading to larger areas affected by excessive PM(2.5) concentration

Evaluation on Green Concept of High-rise Building Design and Its Architectural Feasibility

Recently, the feasibility study on occupancy, building design and its operation are critical issues in building certification. This study evaluates green concept of a high-rise building, Grand Darmo Suite Hotel Surabaya-an awarded on green building as case study, to the architectural feasibility. The modeling using Ecotect Analysis and CFD Fluent program combined with field observation were also conducted to evaluate the building performance. Based on building simulation and the walkthrough survey and audit, the results show that the building has architectural aspect and advantage, it remains in consistent way between the initial planning and the development. In general, the green concept is implemented in organization of space and its use where they are in accordance with the functions and appropriate to building permit. Furthermore, the condition and quality of the finishing material do not interfere the comfort of occupancy

Evaluation on green concept of high-rise building design and its architectural feasibility

Recently, the feasibility study on occupancy, building design and its operation are critical issues in building certification. This study evaluates green concept of a high-rise building, Grand Darmo Suite Hotel Surabaya-an awarded on green building as case study, to the architectural feasibility. The modeling using Ecotect Analysis and CFD Fluent program combined with field observation were also conducted to evaluate the building performance. Based on building simulation and the walkthrough survey and audit, the results show that the building has architectural aspect and advantage, it remains in consistent way between the initial planning and the development. In general, the green concept is implemented in organization of space and its use where they are in accordance with the functions and appropriate to building permit. Furthermore, the condition and quality of the finishing material do not interfere the comfort of occupancy

Tools for Optimization of Biomass-to-Energy Conversion Processes

Biomasses are renewable sources used in energy conversion processes to obtain diverse products through different technologies. The production chain, which involves delivery, logistics, pre-treatment, storage and conversion as general components, can be costly and uncertain due to inherent variability. Optimization methods are widely applied for modeling the biomass supply chain (BSC) for energy processes. In this qualitative review, the main aspects and global trends of using geographic information systems (GISs), linear programming (LP) and neural networks to optimize the BSC are presented. Modeling objectives and factors considered in studies published in the last 25 years are reviewed, enabling a broad overview of the BSC to support decisions at strategic, tactical and operational levels. Combined techniques have been used for different purposes: GISs for spatial analyses of biomass; neural networks for higher heating value (HHV) correlations; and linear programming and its variations for achieving objectives in general, such as costs and emissions reduction. This study reinforces the progress evidenced in the literature and envisions the increasing inclusion of socio-environmental criteria as a challenge in future modeling efforts

Fire Safety and Management Awareness

To ensure a healthy lifestyle, fire safety and protocols are essential. The population boom, economic crunches, and excessive exploitation of nature have enhanced the possibilities of destruction due to an event of a fire. Computational simulations enacting case studies and incorporation of fire safety protocols in daily routines can help in avoiding such mishaps

Mitigation of urban storm water runoff through application of computational fluid dynamics

This thesis covers computational methods for improving the ability of green roofs to mitigate storm water runoff in urban environments. Roofs with living vegetation, known as green roofs, have been used for this purpose however quantification of their ability to slow and stop rainfall runoff has not been undertaken to a large degree. In this work two different approaches are taken: i) to improve green roof performance by optimizing their location on a building facade; and ii) to optimize the design of the growth substrate by examining the impact of the porous microstructure on infiltrating flow. The approach for optimization by placement makes use of traditional computational fluid dynamics and applies a full turbulence model to an Eulerian multiphase system consisting of a steady-state wind phase and a set of transient rainfall phases. The rainfall phases are determined by droplet size and the quantity incident upon the building facade is calculated and compared to experimental results. The analysis shows that the accuracy varies widely dependent upon location upon the structure and several sources of error are discussed. The second approach makes use of the lattice Boltzmann technique to aid in the deisgn of the growth substrate. Several representative porous media are generated using monodisperse randomly packed particles and gravity-driven infiltration is tracked from an initialized standing water height above the porous subdomain. Many aspects of the flow and properties of the microstructure are analyzed and conclusions are drawn based upon such factors as interfacial area, saturation rate, capillary pressure, and pore size distribution. Guidelines are drawn to aid in the design of thin homogeneous growth substrates based upon the findings. These ideal cases are compared to simulations performed on XMT scans of real growth substrate material and some conclusions are drawn on the observed differences

Numerical Simulations of the Urban Microclimate

As global urbanization is accelerating and the majority of the world\u27s population continues to reside in cities, sustainable urban development is becoming increasingly crucial. Evaluation of the urban microclimate is a vital aspect of planning sustainable cities, as it can significantly impact on the health and comfort of urban residents. Computational Fluid Dynamics is a cost-effective and flexible tool to predict microclimate conditions, although often not utilized in the urban planning process until the final stages of a project due to complex pre-processing. The current practice of urban planning also often involves simulating different physical phenomena in separate tools, making it difficult to understand the interaction. This thesis presents the potential of the numerical immersed boundary framework IBOFLow as a tool for urban planners to evaluate the urban microclimate at the early stages of the design processes. The complex and time-consuming pre-processing of urban regions is eliminated using automatically generated Cartesian octree grid meshes where the complex geometries are represented by the immersed boundary methodology. The framework is validated for wind using wind tunnel experiments and compared to a commercially used software to show the importance of including the complex local terrain to generate realistic results. Finally, initial results of the heat simulations are covered to visualize the idea of IBOFlow as a means to simulate the urban microclimate at large, including all necessary physics