Wave Drag in Frontcrawl Swimming

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Wave Drag in Front-crawl Swimming

• Huub Toussaint, Maartje van Stralen, Eric Stevens
• Institute for Fundamental and Clinical Human
  Movement Science
• The Netherlands

www.ifkb.nl/B4/indexsw.html H_M_Toussaint_at_fbw.vu.n
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Drag
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v
ship
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ship
Divergent waves
Transverse waves
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Effect of speed on wave length
(of ship)
Wave drag 70 of total drag
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Pieter swimming at 13.5 on 25 m
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Pieter swimming at 10.6 on 25 m
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Length of surface wave
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Hull speed for a swimmer
Height of swimmer 2 m
Pieter swims gt 2 m/s..
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Summary

• humans swim faster than hull speed
• wave drag seems to matter at competitive swimming
  speeds given that for ships wave drag amounts to
  70 of total drag

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Can we estimate wave drag and assess its relative
importance?
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MAD-system
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19v2
15v2.7
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Swimming speed effect on height of the stern wave
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Wave drag as of total drag
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Conclusions

• Wave drag amounted to 12 of total drag.
• The magnitude of wave drag is less than expected
  given speeds gt110 of hull speed
• Nevertheless, it is still worthwhile to dive
  under the wave drag after start and turns.
• The lower than expected wave drag might be
  attributed to swimming technique.

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Technique could reduce the bow wave

• Glide phase arm functions as bulbous bow
  reducing bow wave formation

ship

• Non-stationarity of rostral pressure point
  prohibits full build-up of bow wave

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THANK YOU FOR YOURATTENTION
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Energy method
Epot Mass g 2h/p
Y h sin(px/a)
P Epot v/a
area 2 h a / p
Volume area b 2
Wave drag P / v
Mass volume 1000
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Results
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Takamoto M., Ohmichi H. Miyashita M. (1985)
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Can we estimate wave drag and assess its relative
importance?

• technique seems to influence wave drag