TY - JOUR
T1 - The effect of hand posture on swimming efficiency
AU - van den Berg, Joris
AU - Bazuin, Rens
AU - Jux, Constantin
AU - Sciacchitano, Andrea
AU - Westerweel, Jerry
AU - van de Water, Willem
PY - 2021
Y1 - 2021
N2 - Abstract: Our quest is for the thumb and finger positions that maximize drag in front crawl swimming and thus maximize propulsion efficiency. We focus on drag in a stationary flow. Swimming is in water, but using Reynolds similarity the drag experiments are done in a wind tunnel. We measure the forces on real-life models of a forearm with hands, flexing the thumb and fingers in various positions. We study the influence on drag of cupping the hand and flexing the thumb. We find that cupping the hand is detrimental for drag. Swimming is most efficient with a flat hand. Flexing the thumb has a small effect on the drag, such that the drag is largest for the opened (abducted) thumb. Flow structures around the hand are visualized using robotic volumetric particle image velocimetry. From the time-averaged velocity fields we reconstruct the pressure distribution on the hand. These pressures are compared to the result of a direct measurement. The reached accuracy of ≈ 10% does not yet suffice to reproduce the small drag differences between the hand postures. Graphical Abstract: [Figure not available: see fulltext.].
AB - Abstract: Our quest is for the thumb and finger positions that maximize drag in front crawl swimming and thus maximize propulsion efficiency. We focus on drag in a stationary flow. Swimming is in water, but using Reynolds similarity the drag experiments are done in a wind tunnel. We measure the forces on real-life models of a forearm with hands, flexing the thumb and fingers in various positions. We study the influence on drag of cupping the hand and flexing the thumb. We find that cupping the hand is detrimental for drag. Swimming is most efficient with a flat hand. Flexing the thumb has a small effect on the drag, such that the drag is largest for the opened (abducted) thumb. Flow structures around the hand are visualized using robotic volumetric particle image velocimetry. From the time-averaged velocity fields we reconstruct the pressure distribution on the hand. These pressures are compared to the result of a direct measurement. The reached accuracy of ≈ 10% does not yet suffice to reproduce the small drag differences between the hand postures. Graphical Abstract: [Figure not available: see fulltext.].
UR - http://www.scopus.com/inward/record.url?scp=85119365477&partnerID=8YFLogxK
U2 - 10.1007/s00348-021-03333-1
DO - 10.1007/s00348-021-03333-1
M3 - Article
AN - SCOPUS:85119365477
SN - 0723-4864
VL - 62
JO - Experiments in Fluids
JF - Experiments in Fluids
IS - 12
M1 - 245
ER -