Blubber and compliant coatings for drag reduction in fluids III: viscoelastic properties of dolphin blubber matched by a gel-foam composite

Edwin R. Fitzgerald; James W. Fitzgerald

doi:10.1117/12.237056

26 April 1996 Blubber and compliant coatings for drag reduction in fluids III: viscoelastic properties of dolphin blubber matched by a gel-foam composite

Edwin R. Fitzgerald, James W. Fitzgerald

Author Affiliations +

Proceedings Volume 2779, 3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials; (1996) https://doi.org/10.1117/12.237056
Event: 3rd International Conference on Intelligent Materials, 1996, Lyon, France

Abstract

In contrast to the unsuccessful efforts of many investigators to reduce underwater drag by the use of thin compliant coatings designed to simulate dolphin skin, it was suggested in prior publications in this series that the dolphin's delay in the onset of boundary layer turbulence and reduced drag results from the `intelligent' properties of the thick blubber underlying its skin. The blubber is supposed to have viscoelastic properties such that the dolphin acts as a compliant layer load of mechanical shear impedance, Z_L, which matches the impedance, Z_G, of incipient boundary layer turbulence acting as an equivalent shear force generator. Under this matched condition maximum power transfer and energy absorption in the blubber then quenches continued boundary layer turbulence and restores laminar flow. A gel-foam composite with frequency variations of complex shear compliance and shear modulus close to those of dolphin blubber is described, and suggested as a composite system for use in thick compliant material coatings for drag reduction.

Citation Download Citation

Edwin R. Fitzgerald and James W. Fitzgerald "Blubber and compliant coatings for drag reduction in fluids III: viscoelastic properties of dolphin blubber matched by a gel-foam composite", Proc. SPIE 2779, 3rd International Conference on Intelligent Materials and 3rd European Conference on Smart Structures and Materials, (26 April 1996); https://doi.org/10.1117/12.237056

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