Competitive swimming has always been a traditional sport, with performance being governed by athlete instinct and feel, the coaches’ experience and time spent in the water. However in recent years the introduction and subsequent banning of the ‘super’ suits has opened the eyes of the sport to what science and engineering can achieve. The focus of improvement is often on generating more propulsive force; however increases in swimming speed can be achieved for the same propulsive power if the resistance is reduced. The resistance acting on a freestyle swimmer is governed by the complex unsteady flow regime, featuring significant body and arm motions, large separated regions and interactions with the free surface. Physically simulating all these aspects within a CFD methodology is computationally very expensive. However it is unclear which unsteady flow features need to be included to accurately represent the active resistance of a freestyle swimmer. The unsteady fluid flow around a freestyle swimmer has be investigated numerically through the use of a combine free surface RANS methodology with the impact of the arms represented using a generic body force model. A detailed analysis of a passive swimmer on the surface has been conducted identifying that free surface interactions have a significant effect on the resistance components of a freestyle swimmer and should be included within future research aimed at reducing resistance. The impact of the arms in the propelled simulations produced a significant variation in total resistance due to free surface interactions, highlighting the importance of the arm entry phase of the stroke. However the arms caused no significant change in the mean resistance and the impact of the arm induced velocities on the resistance is very small. Therefore it is concluded that the effect of the arms are not required in an assessment of mean propelled resistance in freestyle swimming.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581537 |
| Date | January 2013 |
| Creators | Banks, Joe |
| Contributors | Turnock, Stephen |
| Publisher | University of Southampton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://eprints.soton.ac.uk/355711/ |
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