Drag Reduction in a Swimming Humboldt Penguin, Spheniscus Humboldti, when the Boundary Layer is Turbulent
An area of protruding feathers found around the beak of many penguin species is thought to induce a turbulent boundary layer whilst swimming. Hydrodynamic tests on a model Humboldt penguin, Spheniscus humboldti, suggest that induced turbulence causes a significant reduction in boundary layer height, flow separation, and an average of 31% reduction in drag (1.0 m/s to 4.5 m/s). Visualisation of surface flow showed it to follow the body profile, over the feet and tail, before separating. Movement of the feet in swimming penguins correlates with steering of the bird. Induced turbulence may therefore further increase swimming efficiency by reducing the amount of foot movement required to direct the swimming bird.
作 者： Alex R. Parfitt Julian F.V. Vincent 作者单位： Centre for Biomimetic and Natural Technologies, Department of Mechanical Engineering, The University of Bath, Bath, BA2 7AY, UK 刊 名： 仿生工程学报（英文版） SCI 英文刊名： JOURNAL OF BIONICS ENGINEERING 年，卷(期)： 2005 2(2) 分类号： Q81 TB17 关键词： drag drag reduction boundary layer turbulence penguin Spheniscus humboldti (Sphenisciformes)