Flow visualization study of synthetic flow control in the indoor environment

An experimental flow visualization study was conducted to assess the ability of synthetic jets to control airflows and particulates in an indoor environment. Flow visualization was used to determine whether paired synthetic jet modules installed adjacent to a supply diffuser could significantly impact room air distribution by changing the angle at which the supply air left the diffuser and mixed into the room. Controlling the supply jet angle can affect how the supply air mixes with the room air and potentially impact the air quality of the room. A laboratory room with 7 air changes per hour (ACH) was selected to perform the present study. This lab space is representative of occupational indoor environments requiring ventilation strategies beyond typical systems to ensure the safe and efficient operation of the space. In this study, four synthetic-jet modules were tested, including two pairs of small 0.5 mm by 27.5 mm rectangular jets driven by one-inch diameter actuators used in a previous small-scale ventilation study and two larger 0.5 mm by 55 mm rectangular jets driven by two-inch diameter actuators constructed specifically for this study. Statistical methods were used to compare the visualized supply flow controlled with active synthetic jets versus a baseline case (with no flow control). A significant increase in the angle of mixing of the supply air of up to 4° or 50% of the original supply jet angle was achieved.