Paper Conference

Proceedings of BSA Conference 2019: Fourth Conference of IBPSA-Italy


Wind and urban spaces. Evaluation of a CFD parametric framework for early‐stage design

Viola Maffessanti

Abstract: Outdoor comfort and microclimate have recently garnered growing interest as important factors determining the success of urban open spaces. Increasing urban density, amongst the consequences of global urbanisation, is considered environmentally positive, but can also have a negative impact on outdoor comfort and on the Urban Heat Island (UHI). Wind plays an important role in alleviating UHI and ensuring comfortable outdoor conditions. However, accelerated winds around tall buildings can cause down-draughts, negatively affecting pedestrian comfort and safety. Monitoring airflow behaviours from the earliest design stages is crucial to adjusting the design accordingly. Expensive physical wind tunnels and sophisticated Computational Fluid Dynamics (CFD) are mainly the domain of wind engineers, while there is an overall lack of fast, intuitive, and yet accurate tools for non-specialists, such as urban designers and architects, particularly involved in the first design phases, to test several design options. Recently, CFD has been fully integrated within the user-friendly and fast-responsive Parametric Design platform, where several environmental simulations can be combined. The aim of this work is to evaluate CFD parametric tools from an accuracy and speed point of view, as a possible solution for non-specialist designers to simulate wind. A CFD parametric framework describing the systematic process to correctly perform airflow simulations with these tools was set-up and included best practice guidelines, a CFD parametric model construction and verification tests. Time was recorded across all simulations. Coupling CFD and parametric design proved positive, in terms of high accuracy and modelling time reduction, thanks to the automatization of some steps. However, the simulations required a long time and some CFD specialist knowledge, limiting the use by non-specialists. Improvements to this technology, computing time reduction strategies and future research were proposed.
Pages: 67 - 76