High-resolution street-scale modeling with LES models

Abstract: As the sustainability implementation requirements at the urban level are far-reaching due to extreme weather and climate events, the need for adequate, efficient, and high-fidelity modelling tools also increases. Cities lack the resilience to withstand extreme events, and the vulnerability of urban dwellers is elevated. Today, air quality and thermal comfort deterioration in urban environments are central concerns that shape mitigation policies and urban climate research. However, finding an appropriate way to understand the local urban atmosphere, recognise issues, and produce reliable information and solutions is complex and multibranched. It requires not only high-end numerical tools, software, observation networks, and urban datasets, but also careful planning, interpretation, and cooperation between the expert community and public administration.

The cornerstone of any scientific investigation of certain phenomena lies in understanding the physical processes that drive them and govern their evolution. The physical framework of the urban boundary layer is a delicate balance of various physical processes that affect the urban atmosphere, airflow, and phenomena within it. This framework is simultaneously influenced by urban morphology and the specificity of settlement patterns. Despite being distinctive on a broader scale, urban areas share a common trait of being heterogeneous with a range of artificial and natural surfaces covering them. Along with large-scale atmospheric dynamics, human activities, etc., these traits make cities hotbeds for turbulence generation. Turbulence is a governing mechanism shaping urban atmospheric behaviour, energy balance, pollutant transport, and street-scale airflow dynamics. It is certainly fundamental and needs to be adequately resolved, with its influence on the urban atmospheric processes accurately represented in the models. Resolving the urban morphology and the boundary layer on a fine scale via numerical models is a prerequisite for understanding urban ventilation, air quality, and thermal comfort and progressing in climate change adaptation and mitigation.

This presentation addresses these critical urban climate issues by utilising Large-Eddy Simulation (LES) to achieve high-resolution, street-scale modelling. The Parallelized Large-Eddy Simulation Model (PALM), a state-of-the-art computational framework designed specifically for the urban canopy is introduced. The presentation will detail PALM’s advanced capabilities, including its sophisticated treatment of urban surfaces, plant canopy effects, and high-resolution turbulence resolving features.

Computer scienceMathematics

Audience: researchers in the topic

Modelling of materials - theory, model reduction and efficient numerical methods (UNCE MathMAC)