Gliding locomotion of manta rays, killer whales and swordfish near the water surface

• Published in: Scientific Reports
• Main Authors: Jie-Min Zhan, Ye-Jun Gong, Tian-Zeng Li
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2017
• Subjects: Medicine; R; Science; Q; Killer Whale; Killer whale
• Online Access: https://doi.org/10.1038/s41598-017-00399-y; https://doaj.org/article/0607b496c72541ff90e8c1148b2e5955

Abstract The hydrodynamic performance of the locomotive near the water surface is impacted by its geometrical shape. For marine animals, their geometrical shape is naturally selective; thus, investigating gliding locomotion of marine animal under the water surface may be able to elucidate the influence of the geometrical shape. We investigate three marine animals with specific geometries: the killer whale is fusiform shaped; the manta ray is flat and broad-winged; and the swordfish is best streamlined. The numerical results are validated by the measured drag coefficients of the manta ray model in a towing tank. The friction drag of the three target models are very similar; the body shape affected form drag coefficient is order as swordfish < killer whale < manta ray; the induced wave breaking upon the body of the manta ray performs different to killer whale and swordfish. These bio-inspired observations provide a new and in-depth understanding of the shape effects on the hydrodynamic performances near the free surface.