Talk:Aquatic locomotion

Latest comment: 6 years ago by Kjellmikal in topic Froude number and Froude efficiency

Froude number and Froude efficiency

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The Froude number and Froude efficiency are two different measures and should not be confused here. The Froude number has to do with surface waves resisting against a moving hull, whereas Froude efficiency is a ratio of power output to power input. This can be measured in a number of ways, but a common way is    /   .

Where   is the non-dimensional coefficient of thrust and   is the non-dimensional coefficient of power.

It doesn't really make sense to link to the wiki page for Froude number here, because that number is not about efficiency. Froude efficiency could possibly even get its own page (since it doesn't have one now). Tkemp (talk) 19:12, 22 January 2013 (UTC)Reply


The blanket claim that animal jet propulsion is inefficient is inaccurate

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Some of the fundamental claims of the jet propulsion section (e.g. "…jet-propulsion is a relatively inefficient method of aquatic locomotion" […] "The metabolic cost of transport for jellyfish is high when compared to a fish of equal mass.") appear to be based on an understanding of comparative aquatic locomotion that is not up to date. Excerpt from a recent study:

"By accounting for large interspecific differences in net metabolic rates, we demonstrate, contrary to prevailing views, that the jellyfish (Aurelia aurita) is one of the most energetically efficient propulsors on the planet, exhibiting a cost of transport (joules per kilogram per meter) lower than other metazoans.[…]

Potential advantages in swimming efficiency of gelatinous zooplankton locomotion have been previously overlooked because efficiency of swimming is commonly estimated using the Froude number, a metric originally designed to quantify the propulsive performance of ships.

A more comprehensive and ecologically relevant method of estimating energetic costs of locomotion is the net cost of transport (COT) […] a suitable metric for interspecific comparisons of swimming efficiency because the energetic expenditures for generating kinematic and fluid motion are not constant among species. By this measure, the moon jellyfish, Aurelia aurita, expends significantly less energy per unit of wet mass per unit distance traveled than other animals."[1] — Preceding unsigned comment added by Kjellmikal (talkcontribs) 19:06, 29 July 2018 (UTC)Reply

References

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Proposed merge

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