Reduced-Scale Particle Image Velocimetry Measurements and Validation of Steady RANS for Air-Curtain Flows in Buildings

Air infiltration and exfiltration that occur at open building entrances are of concern as these have been repeatedly associated with increased energy demand in buildings. Therefore, air curtains are often used to restrict air infiltration/exfiltration through busy building entrances, thereby limiting the exchange of heat and mass between indoor and outdoor environments. Air curtains are fundamentally turbulent plane impinging jets (TPIJs). This paper presents an experimental analysis of the fluid dynamics of TPIJs under parameters that are representative of air-curtain systems in buildings. Experiments are conducted at reduced scale in a water channel where measurements are taken via particle image velocimetry (PIV). Experimental data is subsequently used to validate computational fluid dynamics (CFD) simulations of the TPIJs based on steady Reynolds-averaged Navier-Stokes (RANS) approximation that is commonly used in air-curtain studies. The validation study shows that RANS simulations are capable of resolving the mean velocity field with reasonable accuracy, especially when employing the renormalization group k-ε turbulence model.