{'fraction_non_alphanumeric': 0.02135561745589601, 'fraction_numerical': 0.005571030640668524, 'mean_word_length': 5.022346368715084, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Experimental investigation of the flow field generated by idealized human foot tapping

In this work, Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV) techniques were employed in order to experimentally investigate the flow field generated by a human foot-tapping during a footstep. Experiments were performed in a 56 × 56 × 56-cm sealed plexiglass tank. A rectangular plate that rotates downward with a controlled velocity was used to mimic the human foot-tapping motion. The PIV results show the formation of two counter-rotating vortices outside the plate as a result of the plate rotation movement. The LDV results show that the maximal velocity in the region under the plate increases with distance from the rotation axis and reaches a maximum at the bottom of the plate. In the outside region, maximal velocity decreases exponentially with distance from the plate. Using these two techniques, the velocity profiles in the vertical direction in front of the plate were compared, and, notably, good agreement was demonstrated between the two techniques.