Vortex-driven pulsating flow control and pollutant transport enhancement in enclosed environment via fluidic oscillators

Proper ventilation is a fundamental strategy for enhancing indoor air quality and creating a healthy indoor environment. However, conventional steady-state air supply systems often cause air stagnation in certain regions of an enclosed environment, leading to the accumulation of high-concentration pollutants. This study proposes a vortex-driven pulsating ventilation system using fluidic oscillators to generate periodic vorticity fields. Through experimental measurements and computational fluid dynamics (CFD) simulations, three source location cases were compared under both steady and unsteady ventilation modes. The Ω-vortex identification was employed to examine the airflow characteristics of the fluidic oscillator ventilation system. The ventilation efficiency, pollutant distribution, and high-concentration gas volume visualization were assessed to evaluate the performance of the pulsating ventilation system. The results demonstrate that the pulsating jet was generated based on the Coandă effect inside the fluidic oscillator, which periodically induces large vortices and drives them to move further in an enclosed environment. These pulsation-induced vortices disrupt symmetric flow patterns, thereby accelerating stagnant zone dissipation and enhancing air mixing. When the pollutant sources were located at the entrainment zone and jet zone, pulsating ventilation increased the ventilation efficiency by 12.65% and 11.80%, respectively. This study highlights that the fluidic oscillator provides a promising approach for creating periodic flow fields, thereby enhancing indoor air quality.