Formation of Ocean Surface Patterns by Cetacean Fluke Oscillations
This paper presents a theory describing the fluid mechanics of whale flukeprints. It contains excerpts of a longer paper recently published in the International Journal of Non-Linear Mechanics special issue on biological structures. Whale flukeprints are smooth oval-shaped water patches that form on the surface of the ocean behind a swimming or diving whale. The prints persist up to several minutes and can be used to track whales cruising near the ocean surface. The motion of the fluke provides a mechanism for shedding vortex rings. The subsequent interaction of the vortex ring with the ocean surface damps the short wavelength capillary waves in the print. The theory suggests that the role of natural surfactants are of secondary importance in the early formation of flukeprints. We describe potential directions for future research, including collection of quantitative data from real flukeprints.
Key wordsWhale flukeprint footprint vortex ring vortex shedding wave damping breakwater surfactant
- .Lauder G, Drucker EG (2002) Forces, fishes, and fluids: Hydrodynamic mechanisms of aquatic locomotion, News Physiol Sci 17:235–240Google Scholar
- .Chu C, Wang C, Hsieh C (1993) An experimental investigation of vortex motions near surfaces. Phys Fluids A Fluid Dyn 5(3):662–676. http://link.aip.org/link/?PFA/5/662/1
- .Song M, Kachman N, Kwon J, Bernal L, Tryggvason G (1991) Vortex ring interaction with a free surface. In: 18th Symposium on Naval Hydrodynamics. The National Academies Press, Washington, DC, pp 479–489Google Scholar
- .Brevik I (1976) Partial wave damping in pneumatic breakwaters. J Hydraulics Div 102(9):1167–1176Google Scholar