Infiltration and transport dynamics in air curtains published in Physical Review Fluids

The final chapter of my PhD thesis has now been published in Physical Review Fluids! In this work, we use large-eddy simulations (LES) together with a Lagrangian particle-tracking framework to investigate where infiltrating fluid originates and how it is transported across an air curtain.

While air curtains can suppress most of the buoyancy-driven exchange through an open doorway, their sealing effectiveness typically saturates at around 85%. Our analysis provides a physical explanation for this limit by identifying two distinct infiltration mechanisms.

Before the air curtain establishes, infiltration is dominated by the gravity current generated by the density difference across the doorway. Once the curtain is established, however, a fundamentally different transport pathway takes over: outdoor fluid is entrained into the turbulent air-curtain core and subsequently detrained into the indoor region, either before or after the curtain impinges on the floor.

The results show that this inherent entrainment–detrainment process is responsible for the remaining 15–20% loss in sealing effectiveness, highlighting an intrinsic limitation of turbulent air curtains and providing insight into how their performance might be improved.

This work was carried out with my supervisors, Vamsi Krishna Chalamalla and Narsing Kumar Jha at IIT Delhi. You can read the paper here.