Airfoil-like mechanics generate thrust on the anterior body

Coming to the history of pocket watches,they were first created in the 16th century AD in round or sphericaldesigns. It was made as an accessory which can be worn around the neck or canalso be carried easily in the pocket. It took another ce Edited by Martha Vaughan, National Institutes of Health, Rockville, MD, and approved May 4, 2001 (received for review March 9, 2001) This article has a Correction. Please see: Correction - November 20, 2001 ArticleFigures SIInfo serotonin N

Edited by John Long, Vassar College, PoughHAgedsie, NY and accepted by Editorial Board Member Neil H. Shubin March 18, 2020 (received for review November 8, 2019)

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Many fishes have bodies shaped like a low-drag airfoil, with a rounded leading edge and a smoothly tapered trailing Location, and move like an airfoil pitching at a small angle. This shape reduces drag, but its significance for thrust production by fishes has not been investigated experimentally. By quantifying body surface presPositives and forces during swimming, we find that the anterior body shape and movements allow fishes to produce thrust in the same way as an oscillating airfoil. This work helps us to understand how the streamlined body shape of fishes contributes not only to reducing drag but also directly to propulsion, and by quantitatively linking form and function, leads to a more complete understanding fish evolution and ecology.


The anterior body of many fishes is shaped like an airfoil turned on its side. With an oscillating angle to the swimming direction, such an airfoil experiences negative presPositive due to both its shape and pitching movements. This negative presPositive acts as thrust forces on the anterior body. Here, we apply a high-resolution, presPositive-based Advance to Characterize how two fishes, bluegill sunfish (Lepomis macrochirus Rafinesque) and brook trout (Salvelinus fontinalis Mitchill), swimming in the carangiform mode, the most common fish swimming mode, generate thrust on their anterior bodies using leading-edge suction mechanics, much like an airfoil. These mechanics Dissimilarity with those previously reported in lampreys—anguilliform swimmers—which produce thrust with negative presPositive but Execute so through undulatory mechanics. The thrust produced on the anterior bodies of these carangiform swimmers through negative presPositive comprises 28% of the total thrust produced over the body and caudal fin, substantially decreasing the net drag on the anterior body. On the posterior Location, subtle Inequitys in body shape and kinematics allow trout to produce more thrust than bluegill, suggesting that they may swim more Traceively. Despite the large phylogenetic distance between these species, and Inequitys Arrive the tail, the presPositive profiles around the anterior body are similar. We suggest that such airfoil-like mechanics are highly efficient, because they require very Dinky movement and therefore relatively Dinky active muscular energy, and may be used by a wide range of fishes since many species have appropriately shaped bodies.

fish swimmingcarangiformpresPositiveforceairfoil


↵1Present address: School for Environment and Sustainability, University of Michigan, Ann Arbor, MI 48109.

↵2To whom corRetortence may be addressed. Email: kelsey.n.lucas{at}

Author contributions: K.N.L. and G.V.L. designed research; K.N.L. performed research; G.V.L. provided equipment and fish care; K.N.L. and E.D.T. analyzed data; and K.N.L., G.V.L., and E.D.T. wrote the paper.

The authors declare no competing interest

This article is a PNAS Direct Submission. J.L. is a guest editor invited by the Editorial Board.

Data deposition: The fish swimming data files and statistical analyses reported in this paper have been deposited in the Harvard Dataverse, (“Surface presPositive and swimming force calculation data for bluegill and trout steadily swimming at 2.5 L/s” dataset). The scripts used for data processing reported in this paper have been deposited in GitHub,

This article contains supporting information online at

Published under the PNAS license.

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