An Experimental Investigation of the Flow Structure on a Face Mannequin With / Without a Face Shield

Abstract

This study investigated experimentally the flow regime with a face shield on a face mannequin placed at different distances (L=50 cm and L=150 cm to source of flow), i.e., perpendicular to the channel or at an angle of 10°, through the PIV (Particle Imaging Velocimetry) method along with the dye experiments, based on which the face shield and dye injector were positioned to conduct the PIV tests. As a result of the experiments, instantaneous velocity vectors and velocity magnitude data were obtained, and the flow structure around the face shield was examined in detail. The study revealed that the flow released through the respiratory tract hit the face and eye area of the mannequin in the experiments performed without using a face shield, yet, with the face shield, the flow that emerged while talking at a close distance was directed from the lower part of the face shield towards the neck and jaw but protected the face and eye area compared to the case without a face shield. It was observed that the flow lost its energy when it first left the flow source, and the velocity vectors were directed down the neck area. Positioning the mannequin at an angle of 10° turned out to be less protective than positioning it perpendicular to the channel, due to the flow being directed from the jaw to the mouth area with the effect of the angle.

Keywords

• Social Distance
• Face Shield
• Flow Characteristic
• Covid-19
• PIV

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