Manikin-involved CFD modeling and applications for air flow analysis: A comprehensive review

Human plays an important role in shaping the air flow in built environments. In recent years, an increasing number of studies have incorporated manikins into Computational Fluid Dynamics (CFD) simulations to investigate human effects on airflow and enable more accurate assessments of thermal comfort and health risks. This paper systematically reviews the modeling techniques and applications of manikin-involved CFD airflow simulation. The modeling techniques are reviewed with a focus on the construction of manikin geometry, grid meshing, CFD model selection, along with the verification and validation process. For applications, the manikin-involved simulation enables researchers to assess thermal comfort and contaminant transmission from a human perspective. This includes tracking exhaled contaminants for air quality assessment, applying heat-balance metrics for thermal comfort analysis, and measuring breathing-zone concentration or inhaled dose to assess health risks. It also allows investigation of certain built environment design-related factors (personalized ventilation, partitions) and human-related factors (occupant distribution/behaviors), and serves as a design tool when integrated with an optimization algorithm. Current manikin-involved CFD studies are limited by oversimplified human behavior and a lack of consideration of outdoor and semi-outdoor scenarios. Extending manikin-involved CFD research to outdoor and semi-outdoor scenarios can deliver a human-centric assessment of outdoor thermal comfort and health risks by addressing complex turbulence and diverse urban factors, while facing challenges in selecting manikin complexity, size of the computational domain, and turbulence modeling approaches to balance the accuracy and computational cost.