# Numerical Study of Flow Structure and Pedestrian Level Wind Comfort Inside Urban Street Canyons

## TL;DR

This study uses numerical simulations to analyze airflow and pedestrian comfort in various urban street canyon configurations, providing insights into how geometry influences wind flow and comfort levels.

## Contribution

It introduces a comprehensive numerical approach to evaluate flow structures and pedestrian comfort across different street canyon geometries using RANS simulations.

## Key findings

- Flow patterns vary significantly with canyon geometry.
- Pedestrian comfort maps highlight areas of wind discomfort.
- Turbulent flow conditions are consistent within the studied Reynolds number range.

## Abstract

In this work we numerically investigate the flow conditions inside uniform and non-uniform street canyons well within the atmospheric boundary layer. The numerical simulations use the steady RANS method with the near-wall modelling approach to simulate wall roughness at the boundary. With the aim of investigating both flow structure in broad terms, and pedestrian comfort in the street canyon between parallel buildings, we test different canyon configurations with varied street width, building width and building height. Turbulent conditions are broadly expected to hold within the physically-realistic range of Reynolds number of order $10^6$ considered here, where we take the building height to be a characteristic length scale, and the free stream velocity as the characteristic velocity. In addition to discussing the features of the canyon and wake flow, we investigate the effects of canyon geometry on pedestrian comfort by using the Extended Land Beaufort Scale for this purpose. We present and compare pedestrian comfort maps for each of our geometries.