Numerical investigation of passive and active flapping in fish propulsion

• Applicant: Privatdozent Dr.-Ing. Xiangyu Hu
• Subject Area: Fluid Mechanics
• Term: from 2015 to 2018
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 269137996

The study of swimming hydrodynamics has attracted considerable attention in recent years as engineers and biologists have focused on the remarkable diversity in design and locomotion performance of aquatic organisms. One important difficulty of such study is that how the live fishes achieve much higher propulsion efficiency and stability than that of the up-to-date robotic fishes. Such difficulty hinders the realization of the latter for practical applications. Based on the observations on fish swimming and passive flapping of thin structure in high speed flow, we propose to develop a fundamental understanding of the passive and active flapping, which leads to the eventual realization of high effective artificial carangiform swimmer. The research is based on two-way coupling of flow-structure interaction, and three-dimensional numerical simulations. We apply for two funding periods for 6 years in toal. During the first funding period of 3 years the emphasis will be model development and large eddy simulation, which focuses on the large flow structures and the essential contributions of passive and active flapping and their interplay for increasing propulsion efficiency. In the second funding period we will focus on direct numerical simulations and the active controls relevant to swimming stability. Furthermore, if time permits, we will perform in the second funding period the optimization of the active control parameters to achieve the maximum propulsion efficiency and swimming stability. Such control parameters can be used to direct the design of high effective robotic fish.

• DFG Programme: Research Grants